The ancient parish church of Saint Eulalia of Berdún was built as a single nave at the end of the 15th century and beginning of the 16th century. From that period there remain two doorways; one which is blocked off at the western end and another that remains open on the south side. The latter is of Gothic style and boasts a lightly pointed arch with architraves that rest on slender half-columns closed with capitals. Also of interest is the tympanum made of elements of varied origin. Carved in the stone is the date of its creation 1519 and the name of its probable creator, Miguel de Betania.

The first section of the church pertains to the original construction, together with the choir gallery, furnished in 1528 and reformed in the mid-17th century with beautiful carved stalls by the Master of Sangüesa Gabriel Goarasa. It is documented that in 1612 the Basque Juan de Reyzu was contracted for the first phase of reform works on the temple, which included a complete remodeling of its structure. The first section remained, but the walls were demolished to create two lateral naves at almost the same height.

During that drastic reform many elements of contemporary construction were used, such as the lattice arches that stretch between the columns and the buttresses on the exterior walls.

Inside the church, the main altarpiece is especially noteworthy. Finished in 1604, it displays a perectly ordered Classicist architectural structure. The sculptures are in the formal Romanist Navarran style, as can be seen in the Crucifiction of the chancel on the Gospel side. Also of note is the wealth of 17th and 18th century altarpieces conserved in the church.