The Cathedral of Modena is the primary church of the city and of the Modena-Nonantola Archdiocese.

A Romanesque masterpiece, it was built by the architect Lanfranco on the burial site of St Geminianus, patron saint of Modena, where two churches had previously stood from the 5th century. In the cathedral crypt are two relics of the saint, preserved in a simple 4th-century urn covered by a stone slab and supported by expropriated columns. The sarcophagus, preserved in a glass case, is opened each year on the saint's feast day, 31 January. The saint's remains, clothed in Bishop's attire with the pastoral set beside him, are displayed for the devotion of the faithful.
Beside the cathedral stands the bell-tower known as the Ghirlandina.
The Cathedral of Modena, the Ghirlandina and Piazza Grande were declared UNESCO World Heritage Sites in 1997.

The Cathedral underwent restoration to reinforce it from 2007 to 2008. Some supporting beams that had deteriorated were replaced, and cracks in the walls were repaired. The rose window, which was shown to be rather unstable, was also restored, both its small columns (which were dismantled and reassembled one by one) and the 15th-century multi-coloured glass. The glass in particular underwent in-depth analysis conducted by the University of Padua so as to identify the non-original parts, which had replaced the original pieces over the centuries (and after wars) with low-quality glass; the studies aimed to replace them definitively with more suitable materials.
As regards the façade, the intention is to seize the opportunity to restore the bas-reliefs by Wiligelmo depicting the Stories of Genesis (those on either side of the main entrance particularly need restoring) as well. The southern side, that facing Piazza Grande, is also slated to be restored, as it appears to require some care.

The Cathedral of Modena is a unique and extraordinarily well preserved example of Romanesque style in general, both in its exterior and its exterior. Certain Gothic formal elements were added during the era of the Campionesi masters, but they fit in perfectly with the Romanesque style of Lanfranco and Wiligelmo, which dominates undisputed.