diff --git a/addons/stock/stock.py b/addons/stock/stock.py
index ec281ca73d8..0c0e21fa2b9 100644
--- a/addons/stock/stock.py
+++ b/addons/stock/stock.py
@@ -973,7 +973,7 @@ class stock_picking(osv.osv):
             if picking.invoice_state != '2binvoiced':
                 continue
             payment_term_id = False
-            partner = (picking.purchase_id and picking.purchase_id.partner_id) or (picking.sale_id and picking.sale_id.partner_id) or (picking.address_id and picking.address_id.partner_id)
+            partner =  picking.address_id and picking.address_id.partner_id
             if not partner:
                 raise osv.except_osv(_('Error, no partner !'),
                     _('Please put a partner on the picking list if you want to generate invoice.'))