diff --git a/addons/purchase/purchase.py b/addons/purchase/purchase.py
index d9a02ed836f..00d98ed265c 100644
--- a/addons/purchase/purchase.py
+++ b/addons/purchase/purchase.py
@@ -179,7 +179,7 @@ class purchase_order(osv.osv):
         'shipped_rate': fields.function(_shipped_rate, string='Received', type='float'),
         'invoiced': fields.function(_invoiced, string='Invoiced & Paid', type='boolean', help="It indicates that an invoice has been paid"),
         'invoiced_rate': fields.function(_invoiced_rate, string='Invoiced', type='float'),
-        'invoice_method': fields.selection([('manual','Based on Purchase Order lines'),('order','Based on generated draft invoice'),('picking','Based on receptions')], 'Invoicing Control', required=True,
+        'invoice_method': fields.selection([('manual','Based on Purchase Order lines'),('order','Based on generated draft invoice'),('picking','Bases on incoming shipments')], 'Invoicing Control', required=True,
             help="Based on Purchase Order lines: place individual lines in 'Invoice Control > Based on P.O. lines' from where you can selectively create an invoice.\n" \
                 "Based on generated invoice: create a draft invoice you can validate later.\n" \
                 "Based on receptions: let you create an invoice when receptions are validated."