diff -r b322047fec55 Include/dictobject.h
--- a/Include/dictobject.h	Wed Oct 23 22:27:52 2013 +0300
+++ b/Include/dictobject.h	Wed Oct 23 22:30:53 2013 +0300
@@ -25,6 +25,7 @@
     Py_ssize_t ma_used;
     PyDictKeysObject *ma_keys;
     PyObject **ma_values;
+    size_t ma_count;
 } PyDictObject;
 
 #endif /* Py_LIMITED_API */
diff -r b322047fec55 Lib/test/test_dict.py
--- a/Lib/test/test_dict.py	Wed Oct 23 22:27:52 2013 +0300
+++ b/Lib/test/test_dict.py	Wed Oct 23 22:30:53 2013 +0300
@@ -414,12 +414,25 @@
         self.assertRaises(Exc, d.pop, x)
 
     def test_mutating_iteration(self):
-        # changing dict size during iteration
-        d = {}
-        d[1] = 1
+        # changing dict during iteration
+        d = {i: i for i in range(100)}
         with self.assertRaises(RuntimeError):
             for i in d:
-                d[i+1] = 1
+                d[i + 100] = i + 100
+                del d[i]
+
+        d = {i: i for i in range(100)}
+        with self.assertRaises(RuntimeError):
+            for i, j in d.items():
+                d[i + 100] = i + 100
+                del d[i]
+
+        d = {i: i for i in range(100)}
+        with self.assertRaises(RuntimeError):
+            for i in d.values():
+                d[i + 100] = i + 100
+                del d[i]
+
 
     def test_mutating_lookup(self):
         # changing dict during a lookup (issue #14417)
diff -r b322047fec55 Objects/dictobject.c
--- a/Objects/dictobject.c	Wed Oct 23 22:27:52 2013 +0300
+++ b/Objects/dictobject.c	Wed Oct 23 22:30:53 2013 +0300
@@ -831,12 +831,14 @@
             }
             mp->ma_keys->dk_usable--;
             assert(mp->ma_keys->dk_usable >= 0);
+            mp->ma_count++;
             ep->me_key = key;
             ep->me_hash = hash;
         }
         else {
             if (ep->me_key == dummy) {
                 Py_INCREF(key);
+                mp->ma_count++;
                 ep->me_key = key;
                 ep->me_hash = hash;
                 Py_DECREF(dummy);
@@ -925,6 +927,7 @@
         mp->ma_keys = oldkeys;
         return -1;
     }
+    mp->ma_count++;
     if (oldkeys->dk_lookup == lookdict)
         mp->ma_keys->dk_lookup = lookdict;
     oldsize = DK_SIZE(oldkeys);
@@ -956,6 +959,7 @@
         }
     }
     mp->ma_keys->dk_usable -= mp->ma_used;
+    mp->ma_count++;
     if (oldvalues != NULL) {
         /* NULL out me_value slot in oldkeys, in case it was shared */
         for (i = 0; i < oldsize; i++)
@@ -1237,6 +1241,7 @@
         ENSURE_ALLOWS_DELETIONS(mp);
         old_key = ep->me_key;
         Py_INCREF(dummy);
+        mp->ma_count++;
         ep->me_key = dummy;
         Py_DECREF(old_key);
     }
@@ -2268,6 +2273,7 @@
         *value_addr = defaultobj;
         val = defaultobj;
         mp->ma_keys->dk_usable--;
+        mp->ma_count++;
         mp->ma_used++;
     }
     return val;
@@ -2335,6 +2341,7 @@
     mp->ma_used--;
     if (!_PyDict_HasSplitTable(mp)) {
         ENSURE_ALLOWS_DELETIONS(mp);
+        mp->ma_count++;
         old_key = ep->me_key;
         Py_INCREF(dummy);
         ep->me_key = dummy;
@@ -2403,6 +2410,7 @@
     PyTuple_SET_ITEM(res, 0, ep->me_key);
     PyTuple_SET_ITEM(res, 1, ep->me_value);
     Py_INCREF(dummy);
+    mp->ma_count++;
     ep->me_key = dummy;
     ep->me_value = NULL;
     mp->ma_used--;
@@ -2753,7 +2761,7 @@
 typedef struct {
     PyObject_HEAD
     PyDictObject *di_dict; /* Set to NULL when iterator is exhausted */
-    Py_ssize_t di_used;
+    size_t di_count;
     Py_ssize_t di_pos;
     PyObject* di_result; /* reusable result tuple for iteritems */
     Py_ssize_t len;
@@ -2768,7 +2776,7 @@
         return NULL;
     Py_INCREF(dict);
     di->di_dict = dict;
-    di->di_used = dict->ma_used;
+    di->di_count = dict->ma_count;
     di->di_pos = 0;
     di->len = dict->ma_used;
     if (itertype == &PyDictIterItem_Type) {
@@ -2804,7 +2812,7 @@
 dictiter_len(dictiterobject *di)
 {
     Py_ssize_t len = 0;
-    if (di->di_dict != NULL && di->di_used == di->di_dict->ma_used)
+    if (di->di_dict != NULL && di->di_count == di->di_dict->ma_count)
         len = di->len;
     return PyLong_FromSize_t(len);
 }
@@ -2837,10 +2845,10 @@
         return NULL;
     assert (PyDict_Check(d));
 
-    if (di->di_used != d->ma_used) {
+    if (di->di_count != d->ma_count) {
         PyErr_SetString(PyExc_RuntimeError,
-                        "dictionary changed size during iteration");
-        di->di_used = -1; /* Make this state sticky */
+                        "dictionary was changed during iteration");
+        di->di_count = d->ma_count - 1; /* Make this state sticky */
         return NULL;
     }
 
@@ -2919,10 +2927,10 @@
         return NULL;
     assert (PyDict_Check(d));
 
-    if (di->di_used != d->ma_used) {
+    if (di->di_count != d->ma_count) {
         PyErr_SetString(PyExc_RuntimeError,
-                        "dictionary changed size during iteration");
-        di->di_used = -1; /* Make this state sticky */
+                        "dictionary was changed during iteration");
+        di->di_count = d->ma_count - 1; /* Make this state sticky */
         return NULL;
     }
 
@@ -3000,10 +3008,10 @@
         return NULL;
     assert (PyDict_Check(d));
 
-    if (di->di_used != d->ma_used) {
+    if (di->di_count != d->ma_count) {
         PyErr_SetString(PyExc_RuntimeError,
-                        "dictionary changed size during iteration");
-        di->di_used = -1; /* Make this state sticky */
+                        "dictionary was changed during iteration");
+        di->di_count = d->ma_count - 1; /* Make this state sticky */
         return NULL;
     }