diff --git a/Lib/dumbdbm.py b/Lib/dumbdbm.py
index 84a7665..9e9ffcc 100644
--- a/Lib/dumbdbm.py
+++ b/Lib/dumbdbm.py
@@ -68,7 +68,8 @@
         try:
             f = _open(self._datfile, 'r')
         except IOError:
-            f = _open(self._datfile, 'w', self._mode)
+            f = _open(self._datfile, 'w')
+            self._chmod(self._datfile)
         f.close()
         self._update()
 
@@ -106,7 +107,8 @@
         except self._os.error:
             pass
 
-        f = self._open(self._dirfile, 'w', self._mode)
+        f = self._open(self._dirfile, 'w')
+        self._chmod(self._dirfile)
         for key, pos_and_siz_pair in self._index.iteritems():
             f.write("%r, %r\n" % (key, pos_and_siz_pair))
         f.close()
@@ -152,7 +154,8 @@
     # the in-memory index dict, and append one to the directory file.
     def _addkey(self, key, pos_and_siz_pair):
         self._index[key] = pos_and_siz_pair
-        f = _open(self._dirfile, 'a', self._mode)
+        f = _open(self._dirfile, 'a')
+        self._chmod(self._dirfile)
         f.write("%r, %r\n" % (key, pos_and_siz_pair))
         f.close()
 
@@ -214,6 +217,9 @@
 
     __del__ = close
 
+    def _chmod (self, file):
+        if hasattr(self._os, 'chmod'):
+            self._os.chmod(file, self._mode)
 
 
 def open(file, flag=None, mode=0666):
diff --git a/Lib/test/test_dumbdbm.py b/Lib/test/test_dumbdbm.py
index 63b14b0..a1e34da 100644
--- a/Lib/test/test_dumbdbm.py
+++ b/Lib/test/test_dumbdbm.py
@@ -38,6 +38,20 @@
         self.read_helper(f)
         f.close()
 
+    def test_dumbdbm_creation_mode(self):
+        # On platforms without chmod, don't do anything.
+        if not hasattr(os, 'chmod'):
+            return
+
+        f = dumbdbm.open(_fname, 'c', 0632)
+        f.close()
+
+        import stat
+        st = os.stat(_fname + '.dat')
+        self.assertEqual(stat.S_IMODE(st.st_mode), 0632)
+        st = os.stat(_fname + '.dir')
+        self.assertEqual(stat.S_IMODE(st.st_mode), 0632)
+        
     def test_close_twice(self):
         f = dumbdbm.open(_fname)
         f['a'] = 'b'