diff --git a/addons/account/invoice.py b/addons/account/invoice.py
index 7f8c06b0d39..7a1ff15a2e5 100644
--- a/addons/account/invoice.py
+++ b/addons/account/invoice.py
@@ -1610,6 +1610,9 @@ class res_partner(osv.osv):
         'invoice_ids': fields.one2many('account.invoice.line', 'partner_id', 'Invoices', readonly=True),
     }
     
+    def copy(self, cr, uid, id, default={}, context={}):
+        default.update({'invoice_ids' : False})
+        return super(res_partner, self).copy(cr, uid, id, default, context)
       
 res_partner()