diff -r c3cec0f77eff Lib/test/test_collections.py
--- a/Lib/test/test_collections.py	Tue Oct 20 18:22:36 2015 +0300
+++ b/Lib/test/test_collections.py	Wed Oct 21 22:16:04 2015 +0300
@@ -2033,6 +2033,35 @@ class OrderedDictTests:
         items = [('a', 1), ('c', 3), ('b', 2)]
         self.assertEqual(list(MyOD(items).items()), items)
 
+    def test_dict_setitem(self):
+        OrderedDict = self.module.OrderedDict
+        od = OrderedDict()
+        dict.__setitem__(od, 'spam', 1)
+        self.assertNotIn('NULL', repr(od))
+
+    def test_dict_delitem(self):
+        OrderedDict = self.module.OrderedDict
+        od = OrderedDict()
+        od['spam'] = 1
+        od['ham'] = 2
+        dict.__delitem__(od, 'spam')
+        with self.assertRaises(KeyError):
+            repr(od)
+
+    def test_dict_delitem_2(self):
+        OrderedDict = self.module.OrderedDict
+        class K(str):
+            def __hash__(self):
+                return 1
+        od = OrderedDict()
+        od[K('spam')] = 1
+        od[K('ham')] = 2
+        dict.__delitem__(od, K('spam'))
+        K.__eq__ = lambda self, other: True
+        r = repr(od)
+        self.assertIn('spam', r)
+        self.assertIn('ham', r)
+
 
 class PurePythonOrderedDictTests(OrderedDictTests, unittest.TestCase):
 
diff -r c3cec0f77eff Objects/odictobject.c
--- a/Objects/odictobject.c	Tue Oct 20 18:22:36 2015 +0300
+++ b/Objects/odictobject.c	Wed Oct 21 22:16:04 2015 +0300
@@ -1459,7 +1459,6 @@ odict_repr(PyODictObject *self)
     _Py_IDENTIFIER(__class__);
     _Py_IDENTIFIER(__name__);
     _Py_IDENTIFIER(items);
-    Py_ssize_t count = -1;
     PyObject *pieces = NULL, *result = NULL, *cls = NULL;
     PyObject *classname = NULL;
 
@@ -1474,6 +1473,7 @@ odict_repr(PyODictObject *self)
     }
 
     if (PyODict_CheckExact(self)) {
+        Py_ssize_t count = 0;
         _ODictNode *node;
         pieces = PyList_New(PyODict_SIZE(self));
         if (pieces == NULL)
@@ -1492,8 +1492,20 @@ odict_repr(PyODictObject *self)
             if (pair == NULL)
                 goto Done;
 
-            PyList_SET_ITEM(pieces, ++count, pair);  /* steals reference */
+
+            if (count < PyList_GET_SIZE(pieces))
+                PyList_SET_ITEM(pieces, count, pair);  /* steals reference */
+            else {
+                if (PyList_Append(pieces, pair) < 0) {
+                    Py_DECREF(pair);
+                    goto Done;
+                }
+                Py_DECREF(pair);
+            }
+            count++;
         }
+        if (count < PyList_GET_SIZE(pieces))
+            PyList_GET_SIZE(pieces) = count;
     }
     else {
         PyObject *items = _PyObject_CallMethodIdObjArgs((PyObject *)self,