diff --git a/openerp/osv/orm.py b/openerp/osv/orm.py
index 31b3bf5c807..007b54ee46c 100644
--- a/openerp/osv/orm.py
+++ b/openerp/osv/orm.py
@@ -282,6 +282,9 @@ class browse_null(object):
     def __unicode__(self):
         return u''
 
+    def __iter__(self):
+        raise NotImplementedError("Iteration is not allowed on %s" % self)
+
 
 #
 # TODO: execute an object method on browse_record_list