The cathedral has a total external length of 85 m, and a façade height of 32 m, dimensions which make it the largest Romanesque church in Emilia-Romagna.

The façade, in Veronese pink marble and gilded stone, is horizontally divided by a gallery that dominates the three portals, decorated with capitals and Romanesque statues.

The crypt, on the Greek cross plan, has 108 Romanesque small columns and is home to the relics of Santa Giustina, Saint Justina of Padua, who was co-patron of Piacenza from the ninth century; to her was dedicated the first cathedral, Domus Justinae, which collapsed in 1117 after an earthquake.

Few remains can be traced of the earlier paleochristian basilica, as Piacenza was razed by Totila in 546, during the Gothic War.

[1] During its history the cathedral was host to several minor composers as maestro di cappella including Francesco Maria Bazzani, and Giuseppe Nicolini.