This change will log your Joomla 1.5 users in to your site as soon as they have completed the registration process. Joomla 1.5 Automatic Login in after Registration This works only if the user doesn’t have to confirm his/her registration by email; In "Global Configuration " change "New User Account Activation" to "No"; The registration welcome email will still be sent to user. Open file joomla_root/components/com_user/controller.php in any text editor and go to line 282.