Part of the structure is occasionally used as a place of worship by the Church of Ireland and it includes a bishop's throne among its furniture.

According to tradition, the ecclesial presence at Kilfenora began with Saint Fachanan, who founded a church here in the 6th century.

[2] Part of the ecclesiastical province of Cashel, the diocese only extended over 200 square miles of very thinly populated land.

The oldest part likely is the north wall of the nave showing (now plaster-covered) cyclopean masonry, this turn-of-the-first-millennium building may have been aisled.

[2] According to local tradition, the late 12th- to early 13-century chancel was roofed with an oak ceiling (blue with gold start) until the end of the 18th century.

It is roofless today and features a 15th-century doorway, a 15th-century Gothic sedilia as well as a Romanesque three-light east window with its triangular pillars topped by carved capitals.

It shares some design features such as the three-lighted decorated east window with other structures from the early 13th century, e.g.Corcomroe Abbey, belonging to the style known as the "school of the west".

[2] Today, the cathedral remains in partially ruined state, although restoration work was done by the National Monument Service in the early 2000s.

[citation needed] In 1837, the nave portion of the cathedral was adopted for use as the parish church for Kilfenora.