diff --git a/src/ChangeLog b/src/ChangeLog
index a12519a96c0..09b6d5b10f8 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,7 @@
+2000-10-16  Stefan Monnier  <monnier@cs.yale.edu>
+
+	* keymap.c (keymap_memberp): Ensure that nil is not a member.
+
 2000-10-16  Gerd Moellmann  <gerd@gnu.org>
 
 	* xdisp.c (set_iterator_to_next): Reset box start and end flags of
diff --git a/src/keymap.c b/src/keymap.c
index 7fe8718aa09..fbbbcae3998 100644
--- a/src/keymap.c
+++ b/src/keymap.c
@@ -311,6 +311,7 @@ int
 keymap_memberp (map, maps)
      Lisp_Object map, maps;
 {
+  if (NILP (map)) return 0;
   while (KEYMAPP (maps) && !EQ (map, maps))
     maps = Fkeymap_parent (maps);
   return (EQ (map, maps));