Lording it over Oristano’s skyline, the Duomo's onion-domed bell tower is one of the few remaining elements of the original 14th-century cathedral, itself a reworking of an earlier church damaged by fire in the late 12th century. The free-standing campanile (bell tower), topped by its conspicuous majolica-tiled dome, adds an exotic Byzantine feel to what is otherwise a typical 18th-century baroque complex.

Inside, the look is largely baroque, though the transept chapels survive from the Gothic original. Of the art on display, the work to look for is the Annunziata in the Cappella dell'Annunziata. A 14th-century wooden sculpture, it is believed to have been carved by the Tuscan sculptor Nino Pisano.