 <p>Check for expired sessions on every Page_Init event. If there are too many pages to do this check, this is what I usually do: </p> <ul> <li>I create a base class and inherit from System.Web.UI.Page.</li> <li>Write my redirect logic in the Page_Init event of my base class.</li> <li>Have the rest of my pages inherit from this base class.</li> </ul> <p>Good luck.</p>