The two aisles, vaulted in barrel, have a cycle of frescoes on the life of Saint Cleto and other sacred scenes.
The church, which overlooks the hypogeum of Saint Cleto, stands at two different times. An older chapel dates back to the early sixteenth century, home of the homonymous Brotherhood. In 1643, with the demolition of some private houses, the church was enlarged with the construction of a second nave.