diff --git a/addons/purchase/purchase.py b/addons/purchase/purchase.py
index 45d63b15efe..d44bbfa110a 100644
--- a/addons/purchase/purchase.py
+++ b/addons/purchase/purchase.py
@@ -1017,6 +1017,8 @@ class purchase_order(osv.osv):
                             all(move.invoice_state == 'invoiced' for move in po_line.move_ids if move.state == 'done')
                             and po_line.invoice_lines and all(line.invoice_id.state not in ['draft', 'cancel'] for line in po_line.invoice_lines)):
                         is_invoiced.append(po_line.id)
+                    elif po_line.product_id.type == 'service':
+                        is_invoiced.append(po_line.id)
             else:
                 for po_line in po.order_line:
                     if (po_line.invoice_lines and