diff --git a/gobject/gobject.h b/gobject/gobject.h
index 28996ca77..a2f9af3d8 100644
--- a/gobject/gobject.h
+++ b/gobject/gobject.h
@@ -62,7 +62,7 @@ G_BEGIN_DECLS
  * 
  * Checks whether a valid #GTypeInstance pointer is of type %G_TYPE_OBJECT.
  */
-#define G_IS_OBJECT(object)         (G_TYPE_CHECK_INSTANCE_TYPE ((object), G_TYPE_OBJECT))
+#define G_IS_OBJECT(object)         (G_TYPE_CHECK_INSTANCE_FUNDAMENTAL_TYPE ((object), G_TYPE_OBJECT))
 /**
  * G_IS_OBJECT_CLASS:
  * @class: a #GObjectClass