diff --git a/ChangeLog b/ChangeLog
index 6204a2ef2..11c241171 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2009-05-03  Mike Kestner  <mkestner@novell.com>
+
+	* glib/Object.cs: revert to old LookupType behavior when Handle is
+	not set.  [Fixes #500417]
+
 2009-05-03  Stephane Delcroix  <sdelcroix@novell.com>
 
 	* glib/Idle.cs:
@@ -32,7 +37,7 @@
 
 	* gtk/Widget.custom: Implement signal registration for the
 	Activate, SettScrollAdjustments and key binding signals
- 	in managed code.
+	in managed code.
 
 2009-04-25  Mike Kestner  <mkestner@novell.com>
 
diff --git a/glib/Object.cs b/glib/Object.cs
index c0e6eb8fb..61d1e61d7 100644
--- a/glib/Object.cs
+++ b/glib/Object.cs
@@ -323,9 +323,13 @@ namespace GLib {
 
 		protected GType LookupGType ()
 		{
-			GTypeInstance obj = (GTypeInstance) Marshal.PtrToStructure (Handle, typeof (GTypeInstance));
-			GTypeClass klass = (GTypeClass) Marshal.PtrToStructure (obj.g_class, typeof (GTypeClass));
-			return new GLib.GType (klass.gtype);
+			if (Handle != IntPtr.Zero) {
+				GTypeInstance obj = (GTypeInstance) Marshal.PtrToStructure (Handle, typeof (GTypeInstance));
+				GTypeClass klass = (GTypeClass) Marshal.PtrToStructure (obj.g_class, typeof (GTypeClass));
+				return new GLib.GType (klass.gtype);
+			} else {
+				return LookupGType (GetType ());
+			}
 		}
 
 		protected internal static GType LookupGType (System.Type t)