diff --git a/addons/account/invoice.py b/addons/account/invoice.py
index a290e041f3d..a48a91690c7 100644
--- a/addons/account/invoice.py
+++ b/addons/account/invoice.py
@@ -918,8 +918,14 @@ account_invoice()
 class account_invoice_line(osv.osv):
     def _amount_line(self, cr, uid, ids, prop, unknow_none,unknow_dict):
         res = {}
+        cur_obj=self.pool.get('res.currency')
         for line in self.browse(cr, uid, ids):
-            res[line.id] = round(line.price_unit * line.quantity * (1-(line.discount or 0.0)/100.0),2)
+            if line.invoice_id:
+                res[line.id] = line.price_unit * line.quantity * (1-(line.discount or 0.0)/100.0)
+                cur = line.invoice_id.currency_id
+                res[line.id] = cur_obj.round(cr, uid, cur, res[line.id])
+            else:
+                res[line.id] = round(line.price_unit * line.quantity * (1-(line.discount or 0.0)/100.0),2)
         return res
 
     def _price_unit_default(self, cr, uid, context=None):