diff --git a/mongoengine/base/document.py b/mongoengine/base/document.py
index bcd761720..736e661fa 100644
--- a/mongoengine/base/document.py
+++ b/mongoengine/base/document.py
@@ -663,7 +663,7 @@ def _from_son(cls, son, _auto_dereference=True, only_fields=None, created=False)
         # get the class name from the document, falling back to the given
         # class if unavailable
         class_name = son.get('_cls', cls._class_name)
-        data = dict(("%s" % key, value) for key, value in son.iteritems())
+        data = dict(("%s" % cls._db_field_map.get(key,key), value) for key, value in son.iteritems())
 
         # Return correct subclass for document type
         if class_name != cls._class_name: