diff --git a/addons/account/invoice.py b/addons/account/invoice.py
index 777955d5a8e..2e81c7b054f 100644
--- a/addons/account/invoice.py
+++ b/addons/account/invoice.py
@@ -1622,6 +1622,7 @@ class account_invoice_tax(osv.osv):
                     tax_grouped[key]['tax_amount'] += val['tax_amount']
 
         for t in tax_grouped.values():
+            t['base'] = cur_obj.round(cr, uid, cur, t['base'])
             t['amount'] = cur_obj.round(cr, uid, cur, t['amount'])
             t['base_amount'] = cur_obj.round(cr, uid, cur, t['base_amount'])
             t['tax_amount'] = cur_obj.round(cr, uid, cur, t['tax_amount'])