This is the most interesting building of the urban centre of Iznate. It dates back to the 16th century, but has been restored on two occasions; once in 1884 and then in 1946. It has a single nave some 25 metres long, 7 metres wide and 11 metres high. On the inside there are three chapels on the side of the Gospel nave which contain some quite valuable works like a oil painting of San Francisco de Paula which is said to have been painted by Zurbarán, and an image of the Immaculate Virgin in polychrome wood from the 17th century. As for the exterior, there are six buttresses next to the Gospel nave that are accessed through half-pointed arches and framed within two images that represent Saint Peter and Saint John and crowned by a Jesuit emblem of Jesus Hominum Salvator. The finishing touch to the whole thing is a coat of arms of San Gregorio 7th from the 19th century, which are decorative ornaments that the Duke of Iznate included after the restoration in 1884.