diff --git a/mongoengine/base.py b/mongoengine/base.py
index 2041caa8..2044d630 100644
--- a/mongoengine/base.py
+++ b/mongoengine/base.py
@@ -1338,7 +1338,7 @@ class BaseDocument(object):
             u = '[Bad Unicode data]'
         return '<%s: %s>' % (self.__class__.__name__, u)
 
-    def __unicode__(self):
+    def __str__(self):
         if hasattr(self, '__unicode__'):
             if PY3:
                 return self.__unicode__()