diff --git a/wp-includes/pluggable.php b/wp-includes/pluggable.php
index fab5d41b9..8b895306a 100644
--- a/wp-includes/pluggable.php
+++ b/wp-includes/pluggable.php
@@ -755,7 +755,7 @@ if ( !function_exists('is_user_logged_in') ) :
 function is_user_logged_in() {
 	$user = wp_get_current_user();
 
-	if ( $user->ID == 0 )
+	if ( empty( $user->ID ) )
 		return false;
 
 	return true;