diff --git a/ChangeLog b/ChangeLog
index 606c058bd..92b358a55 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2002-08-09  Mike Kestner <mkestner@speakeasy.net>
+
+	* generator/ObjectGen.cs (GenerateMapper): guard against IntPtr.Zero
+
 2002-08-09  Duncan Mak  <duncan@ximian.com>
 
 	* sample/Fifteen.cs (Position): Made it a property instead of a
diff --git a/generator/ObjectGen.cs b/generator/ObjectGen.cs
index cdc2bbc5b..6588afe95 100644
--- a/generator/ObjectGen.cs
+++ b/generator/ObjectGen.cs
@@ -221,6 +221,9 @@ namespace GtkSharp.Generation {
 			sw.WriteLine ();
 			sw.WriteLine ("\t\tpublic static GLib.Object CreateObject (IntPtr raw)");
 			sw.WriteLine ("\t\t{");
+			sw.WriteLine ("\t\t\tif (raw == IntPtr.Zero)");
+			sw.WriteLine ("\t\t\t\treturn null;");
+			sw.WriteLine ();
 			sw.WriteLine ("\t\t\tstring typename = gtksharp_get_type_name (raw);");
 			sw.WriteLine ("\t\t\tif (!types.ContainsKey(typename))");
 			sw.WriteLine ("\t\t\t\treturn null;");