The Cathedral of Orense, dedicated to San Martín, is the main religious monument in the city.

Dating from the second half of the 12th century and the first half of the 13th century and its High Altar was consecrated in 1188, it is considered one of the great Romanesque temples in Spain and one of the culminating constructions of the Middle Ages in Galicia.

The later additions, which do not disfigure its fundamental unity, constitute a varied sample of the different styles of successive eras (Romanesque, Gothic, Renaissance, Baroque, Neoclassical and current).

Its transitional Romanesque structure (very remarkable in this sense), has a Latin cross plan of eighty-four meters long, three naves separated by cruciform pillars and bent and pointed arches with ribbed vaults.

The architecture has influences from the Cistercian world in some aspects of the architectural structure and from the Compostela school of Mateana in relation to sculpture (especially the decoration of the covers).

The cathedral takes over from the previous basilica from the Swabian period; Some authors place this primitive basilica on the same site as the current cathedral, while others maintain that that Swabian temple would be located in the place that today the Church of Santa María Madre occupies.

The current Cathedral of Orense also includes the dedication of the episcopal see of San Martín de Tours, begun in the Swabian era.