Use of those WP_*_URL constants is actually not recommended. Instead, you should use the functions designed for this purpose. Will produce: http://example.com/blog/wp-content/whatever There’s also plugins_url(), includes_url(), admin_url(), and site_url(). These have been around since WP 2.6. WP 3.0 adds a bunch of new ones, like home_url and network_home_url and so forth. All these work basically