diff --git a/addons/account_voucher/account_voucher.py b/addons/account_voucher/account_voucher.py
index 4f383a1d077..ef2b861bd4e 100644
--- a/addons/account_voucher/account_voucher.py
+++ b/addons/account_voucher/account_voucher.py
@@ -893,6 +893,8 @@ class account_voucher(osv.osv):
         return res
 
     def onchange_journal(self, cr, uid, ids, journal_id, line_ids, tax_id, partner_id, date, amount, ttype, company_id, context=None):
+        if context is None:
+            context = {}
         if not journal_id:
             return False
         journal_pool = self.pool.get('account.journal')