[3] The date of first construction of a church in Llangaffo (a village in Anglesey about 5 miles (8.0 km) south of the county town of Llangefni) is uncertain.

[4][6] The present building, which is in the north-eastern part of the village on the south-eastern side of the B4419 road, was erected in 1846 alongside the churchyard to a design by the Sheffield-based architects Weightman and Hadfield.

[3][8] It was described by the clergyman and antiquarian Harry Longueville Jones (writing in 1846, as the new church was being constructed) as a "very small and unimportant edifice"; he also noted that it was the only medieval building remaining in the parish.

[3][16] A 1937 survey by the Royal Commission on Ancient and Historical Monuments in Wales and Monmouthshire recorded that the church owned a silver cup and a paten dated 1736.

[8] The transept has a number of memorials dating from the 17th century (including one to Edward Wynn), and a stone from the early 7th century inscribed with ..VI / RNIN / FILIUS / CUURIS / CINI / ERE / XIT / HUNC / LAPI / DEM, which likely translates to 'Gwernin, son of Cuurius Cini, set up this stone'.

The path between the road and the church has sunken, which may partly be explained by the medieval custom of burying the dead on top of each other.

One author has suggested that the mound alongside the path might indicate that the church is located in the site of a Bronze Age settlement.

[2] It was given this status on 30 January 1968 and Cadw (the Welsh Assembly Government body responsible for the built heritage of Wales) states that it has been listed because it is "a mid 19th-century rural church, consistently articulated and detailed in an Early English style.

"[3] The 19th-century writer Samuel Lewis said that the rebuilt church "forms a very good specimen of the early English style of architecture", adding that it was "effective from its simplicity and the absence of pretension.

[6] A 2009 guide to the buildings of the region notes the "exceptional number of inscribed fragments", showing it to be a place of early Christian worship, but considers that the church is "unlovely".

[16] Similarly, a 2005 guide to Wales describes St Caffo's as "an uninspiring nineteenth-century church from the outside" but says that it has "a remarkable collection" of memorial stones.