I want to display a different layout according to the particular post’s category so I would edit “ single.php ” as follows: $post = $wp_query -> post ; if ( in_category ( '2' ) ) { include ( TEMPLATEPATH . '/single-blog.php' ) ; } elseif ( in_category ( '15' ) ) { include ( TEMPLATEPATH . '/single-photography.php' ) ; } elseif ( in_category ( '18' ) ) { include ( TEMPLATEPATH . '/single-video.php' ) ; } else { include ( TEMPLATEPATH . '/single-default.php' ) ; } ?>