diff --git a/Lib/ldap/cidict.py b/Lib/ldap/cidict.py
index db57468..3dcfe48 100644
--- a/Lib/ldap/cidict.py
+++ b/Lib/ldap/cidict.py
@@ -58,6 +58,17 @@ def has_key(self, key):
         """Compatibility with python-ldap 2.x"""
         return key in self
 
+    @property
+    def data(self):
+        """Compatibility with older IterableUserDict-based implementation"""
+        warnings.warn(
+            'ldap.cidict.cidict.data is an internal attribute; it may be ' +
+            'removed at any time',
+            category=DeprecationWarning,
+            stacklevel=2,
+        )
+        return self._data
+
 
 def strlist_minus(a,b):
   """
diff --git a/Tests/t_cidict.py b/Tests/t_cidict.py
index b96a26e..6878617 100644
--- a/Tests/t_cidict.py
+++ b/Tests/t_cidict.py
@@ -62,6 +62,16 @@ def test_strlist_deprecated(self):
                 strlist_func(["a"], ["b"])
             self.assertEqual(len(w), 1)
 
+    def test_cidict_data(self):
+        """test the deprecated data atrtribute"""
+        d = ldap.cidict.cidict({'A': 1, 'B': 2})
+        with warnings.catch_warnings(record=True) as w:
+            warnings.resetwarnings()
+            warnings.simplefilter('always', DeprecationWarning)
+            data = d.data
+        assert data == {'a': 1, 'b': 2}
+        self.assertEqual(len(w), 1)
+
 
 if __name__ == '__main__':
     unittest.main()