Index: gobject/pygsource.c
===================================================================
--- gobject/pygsource.c	(revision 729)
+++ gobject/pygsource.c	(working copy)
@@ -116,6 +116,7 @@
     }
 
     g_source_destroy(self->source);
+    g_source_unref(self->source);
     self->source = NULL;
 
     Py_INCREF(Py_None);
