PHP Manual . ... PHP 4 >= 4.0.0) session_destroy -- Destroys all data registered to a session . ... If you are using session_name("something"), don't forget it now! session_start(); // Unset all of the session variables. session_unset(); // Finally, destroy the session. session_destroy(); ?> ... If you are using session_name("something"), don't forget it now! session_start(); // Unset all of the session variables. unset($_SESSION); // Finally, destroy the session. session_destroy(); ?> ...