diff --git a/openerp/fields.py b/openerp/fields.py
index 53f6024d739..7c46361434a 100644
--- a/openerp/fields.py
+++ b/openerp/fields.py
@@ -125,6 +125,9 @@ class Field(object):
             ``one2many`` and computed fields, including property fields and
             related fields)
 
+        :param string oldname: the previous name of this field, so that ORM can rename
+            it automatically at migration
+
         .. _field-computed:
 
         .. rubric:: Computed fields