diff --git a/addons/stock/stock.py b/addons/stock/stock.py
index d2a5265ef13..ddfde0a3f75 100644
--- a/addons/stock/stock.py
+++ b/addons/stock/stock.py
@@ -1583,7 +1583,7 @@ class stock_production_lot(osv.osv):
         'product_id': lambda x, y, z, c: c.get('product_id', False),
     }
     _sql_constraints = [
-        ('name_ref_uniq', 'unique (name, ref, product_id)', 'The combination of serial number, internal reference and product must be unique !'),
+        ('name_ref_uniq', 'unique (name, product_id)', 'The combination of serial number and product must be unique !'),
     ]
 
     def action_traceability(self, cr, uid, ids, context=None):