diff --git a/src/builder/XMLBuilderImpl.ts b/src/builder/XMLBuilderImpl.ts
index a135677..62ea924 100644
--- a/src/builder/XMLBuilderImpl.ts
+++ b/src/builder/XMLBuilderImpl.ts
@@ -377,6 +377,17 @@ export class XMLBuilderImpl implements XMLBuilder {
 
     const importedNode = node.node
 
+    const updateImportedNodeNs = (clone: Element) => {
+      // update namespace of imported node only when not specified
+      if (!clone._namespace) {
+        const [prefix] = namespace_extractQName(
+          clone.prefix ? clone.prefix + ':' + clone.localName : clone.localName
+        );
+        const namespace = hostNode.lookupNamespaceURI(prefix)
+        new XMLBuilderImpl(clone)._updateNamespace(namespace)
+      }
+    };
+
     if (Guard.isDocumentNode(importedNode)) {
       // import document node
       const elementNode = importedNode.documentElement
@@ -385,18 +396,14 @@ export class XMLBuilderImpl implements XMLBuilder {
       }
       const clone = hostDoc.importNode(elementNode, true) as Element
       hostNode.appendChild(clone)
-      const [prefix] = namespace_extractQName(clone.prefix ? clone.prefix + ':' + clone.localName : clone.localName)
-      const namespace = hostNode.lookupNamespaceURI(prefix)
-      new XMLBuilderImpl(clone)._updateNamespace(namespace)
+      updateImportedNodeNs(clone)
     } else if (Guard.isDocumentFragmentNode(importedNode)) {
       // import child nodes
       for (const childNode of importedNode.childNodes) {
         const clone = hostDoc.importNode(childNode, true)
         hostNode.appendChild(clone)
         if (Guard.isElementNode(clone)) {
-          const [prefix] = namespace_extractQName(clone.prefix ? clone.prefix + ':' + clone.localName : clone.localName)
-          const namespace = hostNode.lookupNamespaceURI(prefix)
-          new XMLBuilderImpl(clone)._updateNamespace(namespace)
+          updateImportedNodeNs(clone)
         }
       }
     } else {
@@ -404,9 +411,7 @@ export class XMLBuilderImpl implements XMLBuilder {
       const clone = hostDoc.importNode(importedNode, true)
       hostNode.appendChild(clone)
       if (Guard.isElementNode(clone)) {
-        const [prefix] = namespace_extractQName(clone.prefix ? clone.prefix + ':' + clone.localName : clone.localName)
-        const namespace = hostNode.lookupNamespaceURI(prefix)
-        new XMLBuilderImpl(clone)._updateNamespace(namespace)
+        updateImportedNodeNs(clone)
       }
     }
 
@@ -766,7 +771,7 @@ export class XMLBuilderImpl implements XMLBuilder {
       for (const childNode of ele.childNodes) {
         const newChildNode = childNode.cloneNode(true)
         newEle.appendChild(newChildNode)
-        if (Guard.isElementNode(newChildNode)) {
+        if (Guard.isElementNode(newChildNode) && !newChildNode._namespace) {
           const [newChildNodePrefix] = namespace_extractQName(newChildNode.prefix ? newChildNode.prefix + ':' + newChildNode.localName : newChildNode.localName)
           const newChildNodeNS = newEle.lookupNamespaceURI(newChildNodePrefix)
           new XMLBuilderImpl(newChildNode)._updateNamespace(newChildNodeNS)
diff --git a/test/issues/issue-178.test.ts b/test/issues/issue-178.test.ts
new file mode 100644
index 0000000..4ae0717
--- /dev/null
+++ b/test/issues/issue-178.test.ts
@@ -0,0 +1,57 @@
+import $$ from '../TestHelpers';
+
+describe('Replicate issue', () => {
+  // https://github.com/oozcitak/xmlbuilder2/issues/90
+  describe(`#178 - Namespace is removed when importing fragments.`, () => {
+    const expectedOutput = $$.t`<?xml version="1.0"?><Root xmlns="ns1"><Parent xmlns="ns2"><Child xmlns="ns3"><GrandChild xmlns="ns4">txt</GrandChild></Child></Parent></Root>`;
+    describe(`with defined namespaces on each element`, () => {
+      test(`using .ele()`, () => {
+        const doc = $$.create();
+        const root = doc.ele('ns1', 'Root');
+        const parent = root.ele('ns2', 'Parent');
+        const child = parent.ele('ns3', 'Child');
+        child.ele('ns4', 'GrandChild').txt('txt');
+
+        expect(doc.end()).toBe(expectedOutput);
+      });
+      test(`using .import()`, () => {
+        const doc = $$.create();
+        const root = doc.ele('ns1', 'Root');
+        const parent = $$.fragment().ele('ns2', 'Parent');
+        const child = $$.fragment().ele('ns3', 'Child');
+        const grandChild = $$.fragment().ele('ns4', 'GrandChild').txt('txt');
+
+        child.import(grandChild);
+        parent.import(child);
+        root.import(parent);
+
+        expect(doc.end()).toBe(expectedOutput);
+      });
+    });
+    describe(`with undefined namespaces on parent element`, () => {
+      const expectedOutput = $$.t`<?xml version="1.0"?><Root xmlns="ns1"><Parent><Child xmlns="ns3"><GrandChild xmlns="ns4">txt</GrandChild></Child></Parent></Root>`;
+      test(`using .ele()`, () => {
+        const doc = $$.create();
+        const root = doc.ele('ns1', 'Root');
+        const parent = root.ele('Parent');
+        const child = parent.ele('ns3', 'Child');
+        child.ele('ns4', 'GrandChild').txt('txt');
+
+        expect(doc.end()).toBe(expectedOutput);
+      });
+      test(`using .import()`, () => {
+        const doc = $$.create();
+        const root = doc.ele('ns1', 'Root');
+        const parent = $$.fragment().ele('Parent');
+        const child = $$.fragment().ele('ns3', 'Child');
+        const grandChild = $$.fragment().ele('ns4', 'GrandChild').txt('txt');
+
+        child.import(grandChild);
+        parent.import(child);
+        root.import(parent);
+
+        expect(doc.end()).toBe(expectedOutput);
+      });
+    });
+  });
+});