diff --git a/wp-includes/registration.php b/wp-includes/registration.php
index 74f9f8bcb4..eba8773249 100644
--- a/wp-includes/registration.php
+++ b/wp-includes/registration.php
@@ -176,13 +176,13 @@ function wp_insert_user($userdata) {
 	if ( empty($user_registered) )
 		$user_registered = gmdate('Y-m-d H:i:s');
 
-	$user_nicename_check = $wpdb->get_var( $wpdb->prepare("SELECT ID FROM $wpdb->users WHERE user_nicename = %s AND ID != %d LIMIT 1" , $user_nicename, (int) $ID));
+	$user_nicename_check = $wpdb->get_var( $wpdb->prepare("SELECT ID FROM $wpdb->users WHERE user_nicename = %s AND user_login != %s LIMIT 1" , $user_nicename, $user_login));
 
 	if ($user_nicename_check) {
 		$suffix = 2;
 		while ($user_nicename_check) {
 			$alt_user_nicename = $user_nicename . "-$suffix";
-			$user_nicename_check = $wpdb->get_var( $wpdb->prepare("SELECT ID FROM $wpdb->users WHERE user_nicename = %s AND ID != %d LIMIT 1" , $alt_user_nicename, (int) $ID));
+			$user_nicename_check = $wpdb->get_var( $wpdb->prepare("SELECT ID FROM $wpdb->users WHERE user_nicename = %s AND user_login != %s LIMIT 1" , $alt_user_nicename, $user_login));
 			$suffix++;
 		}
 		$user_nicename = $alt_user_nicename;