 <p>Yes, it is possible. If there was problem with <code>HttpPostAttribute</code>, you would not have been able to get inside <code>LogOn</code> method. You should re-check that fields are sent from client and those fields are put inside request body, not query string. You could check it with chrome for example, by inspecting network traffic or simply by debugging <a href="http://msdn.microsoft.com/en-us/library/system.web.httprequest.form.aspx" rel="nofollow">HttpContext.Current.Request.Form property</a> </p>