diff --git a/lib/sessionmanager.js b/lib/sessionmanager.js
index edd2535f..c39bc6e5 100644
--- a/lib/sessionmanager.js
+++ b/lib/sessionmanager.js
@@ -12,6 +12,8 @@ function SessionManager(options, serializeUser) {
 SessionManager.prototype.logIn = function(req, user, cb) {
   console.log('SM: logIn');
   
+  if (!req.session) { return cb(new Error('Login sessions require session support. Did you forget to use `express-session` middleware?')); }
+  
   var self = this;
   
   // regenerate the session, which is good practice to help
@@ -25,10 +27,6 @@ SessionManager.prototype.logIn = function(req, user, cb) {
       if (err) {
         return cb(err);
       }
-      // TODO: Error if session isn't available here.
-      if (!req.session) {
-        req.session = {};
-      }
       if (!req.session[self._key]) {
         req.session[self._key] = {};
       }