diff --git a/app/controllers/AuthController.php b/app/controllers/AuthController.php
index 1fcb8d6..5c20761 100644
--- a/app/controllers/AuthController.php
+++ b/app/controllers/AuthController.php
@@ -4,6 +4,7 @@ namespace App\Controller;
 
 use App\Controller\ControllerBase,
     App\Model\Data\User,
+    App\Model\Data\UserActivation,
     App\Form\Login as LoginForm,
     App\Form\Registration as RegistrationForm,
     Httpcb\OAuth\UserData\UserDataInterface,
@@ -133,11 +134,39 @@ class AuthController extends ControllerBase
 
             $formData = $this->request->getPost();
             if ($form->isValid($formData)) {
+
+                // Check if email was changed.
+                $activationNeeded = false;
+                if ($form->getValue('email') !== $data->getEmail()) {
+                    $activationNeeded = true;
+
+                    // Set suspended until the email address is confirmed
+                    $user->setStatus(User::STATUS_SUSPENDED);
+                }
+
                 $user->setOAuthId($data->getProvider(), $data->getId());
                 if ($user->save()) {
-                    $this->auth->systemLogin($user);
-                    $this->flash->success('User successfully created. Now add your first callback!');
-                    $this->response->redirect('/callback/new');
+
+                    if ($activationNeeded) {
+
+                        $activation = new UserActivation();
+                        $activation->setUserId($user->getId())
+                            ->save();
+
+                        $content = $this->di->getShared('template')->render('mail/account_activation', [
+                            'link' => $activation->getActivationKey()
+                        ]);
+
+                        $this->di->getMail()->send('Httpcb account activation', $user->getEmail(), $content);
+
+                        $this->flash->success('User successfully created.');
+                        $this->flash->notice("An email has been sent to {$form->getValue('email')} with an activation code.");
+                        $this->response->redirect('/login');
+                    } else {
+                        $this->auth->systemLogin($user);
+                        $this->flash->success('User successfully created. Now add your first callback!');
+                        $this->response->redirect('/callback/new');
+                    }
                 } else {
                     $this->flash->error('Could not create user');
                 }