Index: src/test/java/info/magnolia/nodebuilder/OpsTest.java
===================================================================
--- src/test/java/info/magnolia/nodebuilder/OpsTest.java	(revision 38716)
+++ src/test/java/info/magnolia/nodebuilder/OpsTest.java	(working copy)
@@ -111,4 +111,18 @@
             assertEquals("non-existing", e.getMessage());
         }
     }
+
+    public void testRenamePropertyAndCheckValueForString() throws Exception {
+        final HierarchyManager hm = MgnlContext.getHierarchyManager("config");
+        hm.getRoot().createContent("hello").setNodeData("fooOld", "bar");
+        hm.save();
+
+        final Content root = hm.getContent("/hello");
+        final NodeOperation op = Ops.renameProperty("fooOld", "fooNew");
+        op.exec(root, eh);
+        assertFalse(root.hasNodeData("fooOld"));
+        assertNotNull(root.getNodeData("fooNew"));
+        assertEquals("bar", root.getNodeData("fooNew").getString());
+    }
+
 }
Index: src/test/java/info/magnolia/nodebuilder/NodeBuilderTest.java
===================================================================
--- src/test/java/info/magnolia/nodebuilder/NodeBuilderTest.java	(revision 38716)
+++ src/test/java/info/magnolia/nodebuilder/NodeBuilderTest.java	(working copy)
@@ -70,7 +70,9 @@
                         )
                 ),
                 addNode("other").then(addProperty("X", "Y")),
-                addProperty("lala", "lolo")
+                addProperty("lala", "lolo"),
+                addProperty("oldName", "some String value"),
+                renameProperty("oldName", "newName")
 
         );
         nodeBuilder.exec();
@@ -84,6 +86,9 @@
         assertFalse("Node should have been removed", hm.isExist("/MyRoot/hello/zing"));
         assertFalse("Property should have been removed", hm.isExist("/MyRoot/hello/world/foo"));
         assertEquals(0, messageTracker.getMessages().size());
+        assertFalse(hm.getContent("/MyRoot").hasNodeData("oldName"));
+        assertNotNull(hm.getContent("/MyRoot").getNodeData("newName"));
+        assertEquals("some String value", hm.getNodeData("/MyRoot/newName").getString());
     }
 
     public void testErrorMessages() throws Exception {
Index: src/main/java/info/magnolia/nodebuilder/Ops.java
===================================================================
--- src/main/java/info/magnolia/nodebuilder/Ops.java	(revision 38742)
+++ src/main/java/info/magnolia/nodebuilder/Ops.java	(working copy)
@@ -171,8 +171,15 @@
     public static NodeOperation renameProperty(final String name, final String newName) {
         return new AbstractOp() {
             Content doExec(Content context, ErrorHandler errorHandler) throws RepositoryException {
-                Object value = context.getNodeData(name);
-                context.createNodeData(newName, value);
+                if (!context.hasNodeData(name)) {
+                    throw new ItemNotFoundException(name);
+                }
+                if (context.hasNodeData(newName)) {
+                    //throw new ItemExistsException("Property " + newName + " already exists at " + context.getHandle());
+                    throw new ItemExistsException(newName);
+                }
+                final Value value = context.getNodeData(name).getValue();
+                context.setNodeData(newName, value);
                 context.deleteNodeData(name);
                 return context;
             }
@@ -192,7 +199,7 @@
     }
 
     /**
-     * Copies the node defined by the name parameter in the session. 
+     * Copies the node defined by the name parameter in the session.
      */
     public static NodeOperation copyNode(final String name, final String dest) {
         return new AbstractOp() {