The interior has only one nave. There are remnants of frescos on the walls, the best preserved of which show a precession of men in hoods, called "Los encapuchados" (The hooded ones). The main altar is one of the few from the 16th century that remain in Mexico, made by Simon Pereyns. Another unusual feature is the stonework around the door to the sacristy, which forms a crisscross pattern of flowers.
