diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 49ffb756..a22c5b43 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -13,7 +13,7 @@ env:
   PGPASSWORD: root
 jobs:
   test:
-    name: Julia ${{ matrix.version }} - PostgreSQL ${{ matrix.postgresql-version }} - ${{ matrix.os }} - ${{ matrix.arch }}
+    name: Julia ${{ matrix.version }} - PostgreSQL ${{ matrix.postgresql-version }} - ${{ matrix.os }} - ${{ matrix.arch }} - nonblocking connection(${{ matrix.nonblocking }})
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
@@ -29,6 +29,8 @@ jobs:
         arch:
           - x64
           - x86
+        nonblocking:
+          - "false"
         exclude:
           # Don't test 32-bit on macOS
           - os: macOS-latest
@@ -39,23 +41,48 @@ jobs:
             version: "1.6"
             arch: x64
             postgresql-version: latest
+            nonblocking: "false"
           # Add older supported PostgreSQL Versions
           - os: ubuntu-latest
             version: 1
             arch: x64
             postgresql-version: '13'
+            nonblocking: "false"
           - os: ubuntu-latest
             version: 1
             arch: x64
             postgresql-version: '12'
+            nonblocking: "false"
           - os: ubuntu-latest
             version: 1
             arch: x64
             postgresql-version: '11'
+            nonblocking: "false"
           - os: ubuntu-latest
             version: 1
             arch: x64
             postgresql-version: '10'
+            nonblocking: "false"
+          - os: ubuntu-latest
+            version: 1
+            arch: x64
+            postgresql-version: latest
+            nonblocking: "true"
+          - os: ubuntu-latest
+            version: "1.6"
+            arch: x64
+            postgresql-version: latest
+            nonblocking: "true"
+          - os: windows-latest
+            version: 1
+            arch: x64
+            postgresql-version: latest
+            nonblocking: "true"
+          - os: macOS-latest
+            version: 1
+            arch: x64
+            postgresql-version: latest
+            nonblocking: "true"
     steps:
       - uses: actions/checkout@v2
       - uses: julia-actions/setup-julia@v1
@@ -67,7 +94,7 @@ jobs:
           cache-name: cache-artifacts
         with:
           path: ~/.julia/artifacts
-          key: ${{ runner.os }}-${{ matrix.arch }}-test-${{ env.cache-name }}-${{ hashFiles('**/Project.toml') }}
+          key: ${{ runner.os }}-${{ matrix.arch }}-test-${{ env.cache-name }}-nonblocking-${{ matrix.nonblocking }}-${{ hashFiles('**/Project.toml') }}
           restore-keys: |
             ${{ runner.os }}-${{ matrix.arch }}-test-${{ env.cache-name }}-
             ${{ runner.os }}-${{ matrix.arch }}-test-
@@ -116,6 +143,7 @@ jobs:
           pg_ctl -D $env:PGDATA status
         if: ${{ runner.os == 'Windows' }}
       # Run Tests
+      - run: echo "LIBPQJL_CONNECTION_NONBLOCKING=${{ matrix.nonblocking }}" >> $GITHUB_ENV
       - run: psql -c '\conninfo'
       - uses: julia-actions/julia-buildpkg@latest
       - uses: julia-actions/julia-runtest@latest
diff --git a/src/asyncresults.jl b/src/asyncresults.jl
index 47f5cf62..a69c433f 100644
--- a/src/asyncresults.jl
+++ b/src/asyncresults.jl
@@ -84,7 +84,8 @@ function _consume(jl_conn::Connection)
     # this is important?
     # https://github.com/postgres/postgres/blob/master/src/interfaces/libpq/fe-exec.c#L1266
     # if we used non-blocking connections we would need to check for `1` as well
-    if libpq_c.PQflush(jl_conn.conn) < 0
+    # See _flush(jl_conn::Connection) in connections.jl
+    if !_flush(jl_conn)
         error(LOGGER, Errors.PQConnectionError(jl_conn))
     end
 
@@ -231,7 +232,7 @@ end
 
 function _multi_async_execute(jl_conn::Connection, query::AbstractString; kwargs...)
     async_result = _async_execute(jl_conn; kwargs...) do jl_conn
-        _async_submit(jl_conn.conn, query)
+        _async_submit(jl_conn, query)
     end
 
     return async_result
@@ -252,9 +253,10 @@ function async_execute(
     string_params = string_parameters(parameters)
     pointer_params = parameter_pointers(string_params)
 
-    async_result = _async_execute(jl_conn; binary_format=binary_format, kwargs...) do jl_conn
+    async_result =
+        _async_execute(jl_conn; binary_format=binary_format, kwargs...) do jl_conn
             GC.@preserve string_params _async_submit(
-                jl_conn.conn, query, pointer_params; binary_format=binary_format
+                jl_conn, query, pointer_params; binary_format=binary_format
             )
         end
 
@@ -289,16 +291,22 @@ function _async_execute(
     return async_result
 end
 
-function _async_submit(conn_ptr::Ptr{libpq_c.PGconn}, query::AbstractString)
-    return libpq_c.PQsendQuery(conn_ptr, query) == 1
+function _async_submit(jl_conn::Connection, query::AbstractString)
+    send_status = libpq_c.PQsendQuery(jl_conn.conn::Ptr{libpq_c.PGconn}, query)
+    if isnonblocking(jl_conn)
+        return _flush(jl_conn)
+    else
+        return send_status == 1
+    end
 end
 
 function _async_submit(
-    conn_ptr::Ptr{libpq_c.PGconn},
+    jl_conn::Connection,
     query::AbstractString,
     parameters::Vector{Ptr{UInt8}};
     binary_format::Bool=false,
 )
+    conn_ptr::Ptr{libpq_c.PGconn} = jl_conn.conn
     num_params = length(parameters)
 
     send_status = libpq_c.PQsendQueryParams(
@@ -311,6 +319,11 @@ function _async_submit(
         zeros(Cint, num_params),  # all parameters in text format
         Cint(binary_format),  # return result in text or binary format
     )
-
-    return send_status == 1
+    # send_status must be 1
+    # if nonblock, we also want to _flush
+    if isnonblocking(jl_conn)
+        return send_status == 1 && _flush(jl_conn)
+    else
+        return send_status == 1
+    end
 end
diff --git a/src/connections.jl b/src/connections.jl
index 91372430..23ff808e 100644
--- a/src/connections.jl
+++ b/src/connections.jl
@@ -267,6 +267,7 @@ function Connection(
     throw_error::Bool=true,
     connect_timeout::Real=0,
     options::Dict{String, String}=CONNECTION_OPTION_DEFAULTS,
+    nonblocking::Bool=false,
     kwargs...
 )
     if options === CONNECTION_OPTION_DEFAULTS
@@ -300,7 +301,7 @@ function Connection(
     )
 
     # If password needed and not entered, prompt the user
-    if libpq_c.PQconnectionNeedsPassword(jl_conn.conn) == 1
+    connection = if libpq_c.PQconnectionNeedsPassword(jl_conn.conn) == 1
         push!(keywords, "password")
         user = unsafe_string(libpq_c.PQuser(jl_conn.conn))
         # close this connection; will open another one below with the user-provided password
@@ -309,7 +310,7 @@ function Connection(
         pass = Base.getpass(prompt)
         push!(values, read(pass, String))
         Base.shred!(pass)
-        return handle_new_connection(
+        handle_new_connection(
             Connection(
                 _connect_nonblocking(keywords, values, false; timeout=connect_timeout);
                 kwargs...
@@ -317,11 +318,25 @@ function Connection(
             throw_error=throw_error,
         )
     else
-        return handle_new_connection(
+        handle_new_connection(
             jl_conn;
             throw_error=throw_error,
         )
     end
+
+    if nonblocking 
+        success = libpq_c.PQsetnonblocking(connection.conn, convert(Cint, nonblocking)) == 0
+        if success
+            return connection
+        elseif throw_error
+            close(connection)
+            error(LOGGER, "Could not provide a non-blocking connection")
+        else
+            warn(LOGGER, "Could not provide a non-blocking connection")
+            return connection
+        end
+    end
+    return connection
 end
 
 # AbstractLock primitives:
@@ -672,7 +687,7 @@ end
 """
     ConnectionOption(pq_opt::libpq_c.PQconninfoOption) -> ConnectionOption
 
-Construct a `ConnectionOption` from a `libpg_c.PQconninfoOption`.
+Construct a `ConnectionOption` from a `libpq_c.PQconninfoOption`.
 """
 function ConnectionOption(pq_opt::libpq_c.PQconninfoOption)
     return ConnectionOption(
@@ -789,3 +804,73 @@ function socket(conn::Ptr{libpq_c.PGconn})
 end
 
 socket(jl_conn::Connection) = socket(jl_conn.conn)
+
+"""
+    setnonblocking(jl_conn::Connection; nonblocking=true)
+
+Sets the nonblocking connection status of the PG connections.
+While async_execute is non-blocking on the receiving side,
+the sending side is still nonblocking without this
+Returns true on success, false on failure
+
+https://www.postgresql.org/docs/current/libpq-async.html
+"""
+function setnonblocking(jl_conn::Connection; nonblocking=true)
+    return libpq_c.PQsetnonblocking(jl_conn.conn, convert(Cint, nonblocking)) == 0
+end
+
+"""
+    isnonblocking(jl_conn::Connection)
+Checks whether the connection is non-blocking.
+Returns true if the connection is set to non-blocking, false otherwise
+
+https://www.postgresql.org/docs/current/libpq-async.html
+"""
+function isnonblocking(jl_conn::Connection)
+    return libpq_c.PQisnonblocking(jl_conn.conn) == 1
+end
+
+"""
+    _flush(jl_conn::Connection)
+
+Do the _flush dance described in the libpq docs. Required when the
+connections are set to nonblocking and we want do send queries/data
+without blocking.
+
+https://www.postgresql.org/docs/current/libpq-async.html#LIBPQ-PQFLUSH
+"""
+function _flush(jl_conn::Connection)
+    local watcher = nothing
+    if isnonblocking(jl_conn)
+        watcher = FDWatcher(socket(jl_conn), true, true)  # can wait for reads and writes
+    end
+    try
+        while true
+            flushstatus = libpq_c.PQflush(jl_conn.conn)
+            # 0 indicates success
+            if flushstatus == 0
+                return true
+            # -1 indicates error
+            elseif flushstatus < 0
+                return false
+            # 1 indicates that we could not send all data without blocking, 
+            elseif flushstatus == 1
+                # need to wait FD
+                # Only applicable when the connection is in nonblocking mode
+                wait(watcher)  # Wait for the watcher
+                # If it becomes write-ready, call PQflush again.
+                if watcher.mask.writable
+                    continue  # Call PGflush again, to send more data
+                end
+                if watcher.mask.readable
+                    # if the stream is readable, we have to consume data from the server first.
+                    success = libpq_c.PQconsumeInput(jl_conn.conn) == 1
+                    !success && return false
+                end
+            end
+        end
+    finally
+        # Just close the watcher
+        !isnothing(watcher) && close(watcher)
+    end
+end
diff --git a/test/runtests.jl b/test/runtests.jl
index 6a018f64..08b1ed03 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -40,7 +40,8 @@ function count_allocs(f, args...)
     return Base.gc_alloc_count(stats.gcstats)
 end
 
-@testset "LibPQ" begin
+usenonblocking = get(ENV, "LIBPQJL_CONNECTION_NONBLOCKING", "false") === "true"
+@testset "LibPQ $(usenonblocking ? "(nonblocking connection)" : "")" begin
 
 @testset "ConninfoDisplay" begin
     @test parse(LibPQ.ConninfoDisplay, "") == LibPQ.Normal
@@ -81,7 +82,8 @@ end
     DATABASE_USER = get(ENV, "LIBPQJL_DATABASE_USER", "postgres")
 
     @testset "Example SELECT" begin
-        conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=false)
+        conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=false, nonblocking=usenonblocking)
+        
         @test conn isa LibPQ.Connection
         @test isopen(conn)
         @test status(conn) == LibPQ.libpq_c.CONNECTION_OK
@@ -189,7 +191,7 @@ end
     end
 
     @testset "Example INSERT and DELETE" begin
-        conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER")
+        conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; nonblocking=usenonblocking)
 
         result = execute(conn, """
             CREATE TEMPORARY TABLE libpqjl_test (
@@ -332,7 +334,7 @@ end
 
     @testset "load!" begin
         @testset "issue #204" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER")
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; nonblocking=usenonblocking)
 
             close(execute(conn, """
                 CREATE TEMPORARY TABLE libpqjl_test (
@@ -356,7 +358,7 @@ end
 
     @testset "COPY FROM" begin
         @testset "Example COPY FROM" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER")
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; nonblocking=usenonblocking)
 
             result = execute(conn, """
                 CREATE TEMPORARY TABLE libpqjl_test (
@@ -400,7 +402,7 @@ end
         end
 
         @testset "Wrong column order" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER")
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; nonblocking=usenonblocking)
 
             result = execute(conn, """
                 CREATE TEMPORARY TABLE libpqjl_test (
@@ -457,7 +459,7 @@ end
         @testset "do" begin
             local saved_conn
 
-            was_open = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true) do jl_conn
+            was_open = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking) do jl_conn
                 saved_conn = jl_conn
                 return isopen(jl_conn)
             end
@@ -465,7 +467,7 @@ end
             @test was_open
             @test !isopen(saved_conn)
 
-            @test_throws LibPQ.Errors.PQConnectionError LibPQ.Connection("dbname=123fake user=$DATABASE_USER"; throw_error=true) do jl_conn
+            @test_throws LibPQ.Errors.PQConnectionError LibPQ.Connection("dbname=123fake user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking) do jl_conn
                 saved_conn = jl_conn
                 @test false
             end
@@ -474,14 +476,14 @@ end
         end
 
         @testset "Version Numbers" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             # update this test before PostgreSQL 20.0 ;)
             @test LibPQ.pqv"7" <= LibPQ.server_version(conn) <= LibPQ.pqv"20"
         end
 
         @testset "Encoding" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             @test LibPQ.encoding(conn) == "UTF8"
 
@@ -512,6 +514,7 @@ end
                 options=Dict("IntervalStyle" => "postgres_verbose"),
                 throw_error=true,
                 type_map=Dict(:interval => String),
+                nonblocking=usenonblocking
             )
 
             conn_info = LibPQ.conninfo(conn)
@@ -631,7 +634,8 @@ end
 
         @testset "Finalizer" begin
             closed_flags = map(1:50) do _
-                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER")
+                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; nonblocking=usenonblocking)
+
                 closed = conn.closed
                 finalize(conn)
                 return closed
@@ -645,7 +649,8 @@ end
             results = LibPQ.Result[]
 
             closed_flags = map(1:50) do _
-                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER")
+                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; nonblocking=usenonblocking)
+
                 push!(results, execute(conn, "SELECT 1;"))
                 return conn.closed
             end
@@ -660,7 +665,8 @@ end
 
             # with AsyncResults, which hold a reference to Connection
             closed_flags = asyncmap(1:50) do _
-                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER")
+                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; nonblocking=usenonblocking)
+
                 wait(async_execute(conn, "SELECT pg_sleep(1);"))
                 return conn.closed
             end
@@ -706,7 +712,8 @@ end
             end
 
             @testset "throw_error=false" begin
-                conn = LibPQ.Connection("dbname=123fake user=$DATABASE_USER"; throw_error=false)
+                conn = LibPQ.Connection("dbname=123fake user=$DATABASE_USER"; throw_error=false, nonblocking=usenonblocking)
+
                 @test conn isa LibPQ.Connection
                 @test status(conn) == LibPQ.libpq_c.CONNECTION_BAD
                 @test isopen(conn)
@@ -724,7 +731,8 @@ end
             @testset "throw_error=true" begin
                 @test_throws LibPQ.Errors.PQConnectionError LibPQ.Connection("dbname=123fake user=$DATABASE_USER"; throw_error=true)
 
-                conn = LibPQ.Connection("dbname=123fake user=$DATABASE_USER"; throw_error=false)
+                conn = LibPQ.Connection("dbname=123fake user=$DATABASE_USER"; throw_error=false, nonblocking=usenonblocking)
+
                 @test conn isa LibPQ.Connection
                 @test status(conn) == LibPQ.libpq_c.CONNECTION_BAD
                 @test isopen(conn)
@@ -739,7 +747,7 @@ end
 
     @testset "Results" begin
         @testset "Nulls" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             result = execute(conn, "SELECT NULL"; throw_error=true)
             @test status(result) == LibPQ.libpq_c.PGRES_TUPLES_OK
@@ -823,7 +831,7 @@ end
         end
 
         @testset "Not Nulls" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             result = execute(conn, "SELECT NULL"; not_null=[false], throw_error=true)
             @test status(result) == LibPQ.libpq_c.PGRES_TUPLES_OK
@@ -948,7 +956,7 @@ end
         end
 
         @testset "Tables.jl" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             result = execute(conn, """
                 SELECT no_nulls, yes_nulls FROM (
@@ -990,7 +998,7 @@ end
         end
 
         @testset "Duplicate names" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             result = execute(conn, "SELECT 1 AS col, 2 AS col;", not_null=true, throw_error=true)
             columns = Tables.columns(result)
@@ -1006,7 +1014,7 @@ end
         end
 
         @testset "Uppercase Columns" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             result = execute(conn, "SELECT 1 AS \"Column\";")
             @test num_columns(result) == 1
@@ -1024,7 +1032,7 @@ end
         end
 
         @testset "PQResultError" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             try
                 execute(conn, "SELECT log(-1);")
@@ -1071,7 +1079,7 @@ end
 
         @testset "Type Conversions" begin
             @testset "Deprecations" begin
-                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
                 result = execute(conn, "SELECT 'infinity'::timestamp;")
 
@@ -1088,7 +1096,7 @@ end
             end
 
             @testset "Automatic" begin
-                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
                 result = execute(conn, """
                     SELECT oid, typname, typlen, typbyval, typcategory
@@ -1119,7 +1127,7 @@ end
             end
 
             @testset "Overrides" begin
-                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
                 result = execute(conn, "SELECT 4::bigint;")
                 @test first(first(result)) === Int64(4)
@@ -1168,7 +1176,8 @@ end
 
                 @testset for binary_format in (LibPQ.TEXT, LibPQ.BINARY)
                     @testset "Default Types" begin
-                        conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+                        conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
+
 
                         test_data = [
                             ("3", Cint(3)),
@@ -1334,7 +1343,7 @@ end
                     end
 
                     @testset "Specified Types" begin
-                        conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+                        conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
                         test_data = [
                             ("3", UInt, UInt(3)),
@@ -1427,7 +1436,7 @@ end
         end
 
         @testset "Parameters" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             @testset "Arrays" begin
                 tests = (
@@ -1541,7 +1550,7 @@ end
         end
 
         @testset "SQLString" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER")
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; nonblocking=usenonblocking)
 
             execute(conn, sql```
                CREATE TEMPORARY TABLE libpq_test_users (
@@ -1576,7 +1585,7 @@ end
 
         @testset "Query Errors" begin
             @testset "Syntax Errors" begin
-                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
                 result = execute(conn, "SELORCT NUUL;"; throw_error=false)
                 @test status(result) == LibPQ.libpq_c.PGRES_FATAL_ERROR
@@ -1594,7 +1603,7 @@ end
             end
 
             @testset "Wrong No. Parameters" begin
-                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
                 result = execute(conn, "SELORCT \$1;", String[]; throw_error=false)
                 @test status(result) == LibPQ.libpq_c.PGRES_FATAL_ERROR
@@ -1618,7 +1627,7 @@ end
         end
 
         @testset "Interface Errors" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             result = execute(
                 conn,
@@ -1651,7 +1660,7 @@ end
             ]
 
                 # Establish connection and construct temporary table.
-                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER")
+                conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; nonblocking=usenonblocking)
 
                 # Get the column.
                 result = execute(
@@ -1677,7 +1686,7 @@ end
 
     @testset "Statements" begin
         @testset "No Params, Output" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             stmt = prepare(conn, "SELECT oid, typname FROM pg_type")
 
@@ -1698,7 +1707,7 @@ end
         end
 
         @testset "Params, Output" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             stmt = prepare(conn, "SELECT oid, typname FROM pg_type WHERE oid = \$1")
 
@@ -1723,11 +1732,11 @@ end
         end
     end
 
-    @testset "AsyncResults" begin
+    @testset "AsyncResults (usenonblocking connection=$usenonblocking)" begin
         trywait(ar::LibPQ.AsyncResult) = (try wait(ar) catch end; nothing)
 
         @testset "Basic" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             ar = async_execute(conn, "SELECT pg_sleep(2);"; throw_error=false)
             yield()
@@ -1749,7 +1758,7 @@ end
         end
 
         @testset "Parameters" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             ar = async_execute(
                 conn,
@@ -1781,7 +1790,7 @@ end
 
         # Ensures queries wait for previous query completion before starting
         @testset "Wait in line to complete" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             first_ar = async_execute(conn, "SELECT pg_sleep(4);")
             yield()
@@ -1810,7 +1819,7 @@ end
         end
 
         @testset "Cancel" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             # final query needs to be one that actually does something
             # on Windows, first query also needs to do something
@@ -1842,7 +1851,7 @@ end
         end
 
         @testset "Canceled by closing connection" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             # final query needs to be one that actually does something
             # on Windows, first query also needs to do something
@@ -1874,7 +1883,7 @@ end
         end
 
         @testset "FDWatcher: bad file descriptor (EBADF)" begin
-            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true)
+            conn = LibPQ.Connection("dbname=postgres user=$DATABASE_USER"; throw_error=true, nonblocking=usenonblocking)
 
             ar = async_execute(conn, "SELECT pg_sleep(3); SELECT * FROM pg_type;")
             yield()