diff --git a/lib/sessionlib.php b/lib/sessionlib.php
index 80e2198e97d..a2f24e4a1bf 100644
--- a/lib/sessionlib.php
+++ b/lib/sessionlib.php
@@ -751,6 +751,9 @@ function session_gc() {
             $DB->delete_records('sessions', array('sid'=>$user->sid));
         }
         $rs->close();
+
+        // delete expired sessions for userid = 0 (not logged in)
+        $DB->delete_records_select('sessions', 'userid = 0 AND timemodified < ?', array(time() - $maxlifeitme));
     } catch (dml_exception $ex) {
         error_log('Error gc-ing sessions');
     }