diff --git a/Lib/dumbdbm.py b/Lib/dumbdbm.py
index 200bc7feec2..0ce901fca50 100644
--- a/Lib/dumbdbm.py
+++ b/Lib/dumbdbm.py
@@ -120,7 +120,6 @@ def __setitem__(self, key, val):
 			else:
 				pos, siz = self._addval(val)
 				self._index[key] = pos, siz
-			self._addkey(key, (pos, siz))
 	
 	def __delitem__(self, key):
 		del self._index[key]