diff --git a/addons/stock_account/stock.py b/addons/stock_account/stock.py
index ae5a6ebfb49..e24f00afab2 100644
--- a/addons/stock_account/stock.py
+++ b/addons/stock_account/stock.py
@@ -311,9 +311,15 @@ class stock_picking(osv.osv):
                 invoices[key] = invoice_id
             else:
                 invoice = invoice_obj.browse(cr, uid, invoices[key], context=context)
+                merge_vals = {}
                 if not invoice.origin or invoice_vals['origin'] not in invoice.origin.split(', '):
                     invoice_origin = filter(None, [invoice.origin, invoice_vals['origin']])
-                    invoice.write({'origin': ', '.join(invoice_origin)})
+                    merge_vals['origin'] = ', '.join(invoice_origin)
+                if not invoice.name or invoice_vals['name'] not in invoice.name.split(', '):
+                    invoice_name = filter(None, [invoice.name, invoice_vals['name']])
+                    merge_vals['name'] = ', '.join(invoice_name)
+                if merge_vals:
+                    invoice.write(merge_vals)
 
             invoice_line_vals = move_obj._get_invoice_line_vals(cr, uid, move, partner, inv_type, context=context)
             invoice_line_vals['invoice_id'] = invoices[key]