As is the case of other churches in the area, the church in Jasa is an amalgam of different building stages which left the mark of each architectural and artistic period in its history. The ponderous structure of its main nave and the thick pillars which support the arches of its barrel vault betray its medieval origins. In the 16th century, the nave was divided into four sections covered by star-ribbed vaults.

The temple has a raised choir gallery that resembles a rostrum at the western end. On the Gospel (left) side, the building was extended to include another nave similarly divided into four sections. On the Epistolary (right) side, two private family chapels were added, one with simple ribbed vaults and another with more complex tracery.

Its collection of artwork is of great interest, particularly the altarpieces dated between the 17th and 18th centuries. These show a number of elements common also to pieces in other churches in the Alto Aragon area. The most valuable of these is possibly the altar of Nuestra Señora del Rosario in Romanist style, kept in one of the private chapels on the Epistolary side of the church.