St Mary Magdalene's Church was the parish church of St Clears (NPRN 105024) during the medieval period, belonging to the Deanery of Carmarthen. Between 1147 and 1184 the church was granted as a cell to Cluniac Priory, St Martin-des-Champs, and became the church of St Clears Priory (NPRN 275712). The priory was disolved as an alien cell around 1414, and was granted to All Souls College, Oxford in 1446. In 1991 geophysical survey demonstated the existence of below-ground buildings to the south of the chancel. A well, Ffynnon Fair, is depicted on historic (1906) Ordnance Survey mappping some 210m south of the church.

The church is a Grade II listed building, and is considered to have the best surviving Norman carved work in Carmarthenshire. It is constructed of limestone rubble and consists of three-bayed chancel, four-bayed nave, west tower with three storys (formerly four) and vestry. The circular limestone font with cylindrical stem may date to the twelfth century. The limestone chancel arch is Romanesque in style, and dates to the twelfth century. It is dressed and moulded, with capitals displaying cable-moulded and animal motifs. A slot between the two eastern orders of the chancel arch stops may have held the ends of a rood screen. A former window in the north nave wall is thought to have possibly lit a rood stair. In 1845 a squint was noted to the south of the chancel arch, although this is no longer visible. The chancel's east and south walls have a medieval basal offset, and a cut-out in the plinth of the south wall (just east of the vestry east wall) may represent the scar of the east wall of a medieval east range. The vestry door has a nineteenth century surround in a medieval opening, which may represent former access to the priory's east range: the outline of an arched recess in the exterior wall corresponds with a slight offset halfway up the interior face of the same wall may have supported a timber gallery leading from a former dormitory (east range first floor) to a stairway down to the chancel. Blocked doorways are visible in the exterior walls at the western ends north and south nave walls. The north was blocked before 1845, and the south in 1853. The tower's openings are all medieval, as is its vault. The rest of the tower dates to the sixteenth century. Its stair is no longer accessible from the ground floor, but there is a blocked square doorway with landing at a higher level, suggestive of a former mezzanine floor. The top storey of the tower was removed in 1759. Battlements were erected on the steeple in 1786. The church was restored in 1853-1855, to the designs of architect R. Kyrke Penson. A vestry was added and the nave was re-fenestrated, re-roofed and re-seated. The squint was blocked, as was the east window of the chancel north wall. The church's three bells were recast into four new bells at this time. The church was again restored in 1883-1884, to the designs of Middleton and Son, Westminster and Cheltenham. The vestry was rebuilt to a larger plan, and its (blocked) marble fireplace and octagonal chimney also date to this time. An earlier building between the chancel north wall and nave was removed. The north wall windows were unblocked and rebuilt, and a window was inserted between them. The south wall window was also inserted, as was (probably) the tower's second storey window. The chancel wes re-roofed, re-floored and re-plastered. In 1898 eating apparatus and chamber were installed. the present organ and gallery was installed in 1914.

Sources include:
Cambria Archaeology, 2000, Carmarthenshire Churches, Gazeteer, 48
Ordnance Survey, 1906, second edition 25in

N Vousden, RCAHMW, 6 December 2012