diff --git a/openerp/addons/base/res/res_lang.py b/openerp/addons/base/res/res_lang.py
index b9dacf1c2d8..2729d8e1f84 100644
--- a/openerp/addons/base/res/res_lang.py
+++ b/openerp/addons/base/res/res_lang.py
@@ -194,6 +194,10 @@ class lang(osv.osv):
         return grouping, thousands_sep, decimal_point
 
     def write(self, cr, uid, ids, vals, context=None):
+        if 'code' in vals:
+            for lang in self.browse(cr, uid, ids, context):
+                if lang.code != vals['code']:
+                    raise UserError(_("Language code cannot be modified."))
         self._lang_get.clear_cache(self)
         self._lang_data_get.clear_cache(self)
         return super(lang, self).write(cr, uid, ids, vals, context)