diff --git a/Source/OCMock/OCMArg.m b/Source/OCMock/OCMArg.m
index 063181ac..9902d610 100644
--- a/Source/OCMock/OCMArg.m
+++ b/Source/OCMock/OCMArg.m
@@ -35,7 +35,7 @@ + (void *)anyPointer
 
 + (id __autoreleasing *)anyObjectRef
 {
-    return (id *)0x01234567;
+    return (id *)[self anyPointer];
 }
 
 + (SEL)anySelector
@@ -127,9 +127,9 @@ + (id)resolveSpecialValues:(NSValue *)value
     if(type[0] == '^')
     {
         void *pointer = [value pointerValue];
-        if(pointer == (void *)0x01234567)
+        if(pointer == [self anyPointer])
             return [OCMArg any];
-        if((pointer != NULL) && (object_getClass((id)pointer) == [OCMPassByRefSetter class]))
+        if((pointer != NULL) && [OCMPassByRefSetter ptrIsPassByRefSetter:pointer])
             return (id)pointer;
     }
     else if(type[0] == ':')
diff --git a/Source/OCMock/OCMPassByRefSetter.h b/Source/OCMock/OCMPassByRefSetter.h
index a02c67f5..f3d68ff4 100644
--- a/Source/OCMock/OCMPassByRefSetter.h
+++ b/Source/OCMock/OCMPassByRefSetter.h
@@ -23,4 +23,7 @@
 
 - (id)initWithValue:(id)value;
 
+// Returns YES if ptr is actually a OCMPassByRefSetter
++ (BOOL)ptrIsPassByRefSetter:(void*)ptr;
+
 @end
diff --git a/Source/OCMock/OCMPassByRefSetter.m b/Source/OCMock/OCMPassByRefSetter.m
index b3e20755..8f30459b 100644
--- a/Source/OCMock/OCMPassByRefSetter.m
+++ b/Source/OCMock/OCMPassByRefSetter.m
@@ -19,11 +19,30 @@
 
 @implementation OCMPassByRefSetter
 
+// Stores a reference to each of our OCMPassByRefSetters so that OCMArg can
+// check any given pointer to verify that it is an OCMPassByRefSetter.
+// The pointers are stored as naked pointers with no reference counts.
+// Note: all accesses protected by @synchronized(gPointerTable)
+static NSHashTable *gPointerTable = NULL;
+
++ (void)initialize
+{
+    if (self == [OCMPassByRefSetter class])
+    {
+        gPointerTable = [[NSHashTable hashTableWithOptions:NSPointerFunctionsOpaqueMemory | NSPointerFunctionsOpaquePersonality] retain];
+    }
+}
+
 - (id)initWithValue:(id)aValue
 {
     if((self = [super init]))
     {
         value = [aValue retain];
+        @synchronized(gPointerTable)
+        {
+            // This will throw if somehow we manage to put two of the same pointer in the table.
+            NSHashInsertKnownAbsent(gPointerTable, self);
+        }
     }
 
     return self;
@@ -32,6 +51,11 @@ - (id)initWithValue:(id)aValue
 - (void)dealloc
 {
     [value release];
+    @synchronized(gPointerTable)
+    {
+        NSAssert(NSHashGet(gPointerTable, self) != NULL, @"self should be in the hash table");
+        NSHashRemove(gPointerTable, self);
+    }
     [super dealloc];
 }
 
@@ -47,4 +71,12 @@ - (void)handleArgument:(id)arg
     }
 }
 
++ (BOOL)ptrIsPassByRefSetter:(void*)ptr
+{
+    @synchronized(gPointerTable)
+    {
+        return NSHashGet(gPointerTable, ptr) != NULL;
+    }
+}
+
 @end