The building is an example of mixed Romanesque-Byzantine and Gothic elements, and stands on the site of the former acropolis of the Greek city, the Guasco hill which overlooks Ancona and its gulf.

The edifice is built in white stone from Mount Conero, with apses protruding from the transept's ends and an elevated body, with a dome at the crossing, in correspondence to the nave.

The façade, divided into three section, is preceded by a wide staircase; above it is a 13th-century Romanesque portal formed by a round arch supported by four columns.

The anterior ones stand on lions in Veronese red marble, while the rear ones, added later by Luigi Vanvitelli, are on a simple pedestal.

It is decorated by a series of columns holding ogival arches with reliefs of saints' busts, animal figures and vegetable motifs.

It has an ogival shape with a dodecagonal drum, standing on a square base with small decorative arches.

All the arms are divided into a nave and two aisles, with re-used antique Roman columns with Byzantine capitals.

The presbytery's arms house, in the northern aisles, the sepulchre of Blessed Girolamo Ginelli (d. 1506), made in 1509 by Giovanni Dalmata.