The Baroque interior is 96m long and was completely rebuilt after a terrible earthquake (1703) which nearly destroyed the whole city; it is divided into three aisles that join under the dome. The ceiling is in wood and sequin gold and contains in the centre St. Bernardine's monogram "JHS" and paintings in the other fields. In a chapel in the right aisle there is St. Bernardine's mausoleum, the most relevant Renaissance sculpture work in Abruzzi, by Silvestro dell'Aquila, a pupil of Donatello's.


Inside the second chapel of the right aisle there is an altarpiece, one of the best works by Andrea della Robbia, consisting of an enamelled earthenpiece against a blue background representing the Resurrection of Christ among two pairs of angels, above which there is the Incoronation of the Virgin among the Angels, and four earthenpieces showing the Visitation, Nativity, Magi Adoration and Circumcision.