The entrance portal (1326) was sculpted by Raimondo di Poggio, and includes a statue of St Michael.
The nave of St Michael has a wooden statue of the Angel, and the 15th-century tomb of Bishop Amico Buonamicizia.
Among the works is the main altarpiece depicting St Michael defeats Satan by Giacinto Brandi.
In the first altar on the right is a canvas depicting the Death of San Gaetano by Alessandro Ricci, a follower of Carlo Maratta.
The church organ (1858) was built by Vincenzo Paci of Ascoli Piceno.