diff --git a/mongoengine/dereference.py b/mongoengine/dereference.py
index 453ba14f..0f60c2f5 100644
--- a/mongoengine/dereference.py
+++ b/mongoengine/dereference.py
@@ -220,7 +220,8 @@ class DeReference(object):
                     elif isinstance(v, (dict, SON)) and '_ref' in v:
                         data[k]._data[field_name] = self.object_map.get(v['_ref'].id, v)
                     elif isinstance(v, dict) and depth <= self.max_depth:
-                        data[k]._data[field_name] = self._attach_objects(v, depth, instance=instance, name=name)
+                        item_name = "%s.%s.%s" % (name, k, field_name)
+                        data[k]._data[field_name] = self._attach_objects(v, depth, instance=instance, name=item_name)
                     elif isinstance(v, (list, tuple)) and depth <= self.max_depth:
                         data[k]._data[field_name] = self._attach_objects(v, depth, instance=instance, name=name)
             elif isinstance(v, (dict, list, tuple)) and depth <= self.max_depth:
diff --git a/tests/document/delta.py b/tests/document/delta.py
index 7ec6ee56..95a03861 100644
--- a/tests/document/delta.py
+++ b/tests/document/delta.py
@@ -827,5 +827,29 @@ class DeltaTest(unittest.TestCase):
         org2.reload()
         self.assertEqual(org2.name, 'New Org 2')
 
+    def test_delta_for_nested_map_fields(self):
+        class EmbeddedRole(EmbeddedDocument):
+            type = StringField()
+
+        class EmbeddedUser(EmbeddedDocument):
+            name = StringField()
+            roles = MapField(field=EmbeddedDocumentField(EmbeddedRole))
+
+        class Doc(Document):
+            users = MapField(field=EmbeddedDocumentField(EmbeddedUser))
+            num = IntField(default=-1)
+
+        Doc.drop_collection()
+
+        doc = Doc(num=1)
+        doc.users["007"] = EmbeddedUser(name="Agent007")
+        doc.save()
+
+        d = Doc.objects(num=1).first()
+        d.users["007"]["roles"]["666"] = EmbeddedRole(type="superadmin")
+        delta = d._delta()
+        self.assertEqual(True, "users.007.roles.666" in delta[0])
+        self.assertEqual('superadmin', delta[0]["users.007.roles.666"]["type"])
+
 if __name__ == '__main__':
     unittest.main()