diff --git a/openerp/addons/base/res/res_lang.py b/openerp/addons/base/res/res_lang.py
index 73c14048672..8ce35106e41 100644
--- a/openerp/addons/base/res/res_lang.py
+++ b/openerp/addons/base/res/res_lang.py
@@ -181,6 +181,10 @@ 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 osv.except_osv(_('User Error'), _("Language code cannot be modified."))
         for lang_id in ids :
             self._lang_data_get.clear_cache(self)
         return super(lang, self).write(cr, uid, ids, vals, context)