It is a building of great austerity and simplicity of form both outside and inside where “everything is in place.”

It is covered with a pointed barrel vault that rests on the walls without a molding. The two side altars are included in the walls of the nave, as is the niche to accommodate the baptismal font. It preserves the Romanesque openings, the south-facing door with a semicircular arch and the double-slit windows of the apse, the southern and western façades. Outside, between the apse and the nave, an imposing pediment rises. The west façade ends in a large two-eyed belfry; the date 1710 is engraved on one of the ashlars of the southern eye arch.

The large ashlars, which can be seen at the bottom of some sections of the facing, could confirm the presence of an earlier building. The place name seems to be derived from “mausoleum” and could refer to a nearby low imperial structure. In 1975, a whole series of intercommunicated “silos” were located in the basement of the church. Also, in the rectory building (adjacent to the church and from the 17th century) there is a structure excavated in the subsoil known as the Tuta de Mosoll, which has a Latin cross plan with 7 niches and could be ‘an ancient funerary structure and these are the “columbas ”destroyed that appear in documents of century XII.

The National Art Museum of Catalonia preserves the murals in the apse of the church of Mosoll, badly damaged by a fire in 1936. The theme that can be appreciated is that of chained or intertwined leaves. Also an altar front of the second half of the 13th century structured in two horizontal registers in which twelve disordered scenes of the life of Mary are represented.