Plastered walls, broad C15 panelled barrel roofs to nave and chancel, lean-to ceiling to aisle. Nave roof of 13x6 panels with moulded ribs. Three massive tie-beams on crude oak console brackets. Stone flagged floors. Small chamfered pointed W doorway into tower, plank door. Arcade of four bays with double-chamfered pointed arches on octagonal piers with chamfered plinths and moulded caps. Two steps right across nave and aisle. Nave has door at w end of N wall, up five steps, cambered-headed reveal. Cambered head to medieval N window. Fragment of painted decoration between two nave N windows, in nave NE corner and on nave S wall. S aisle has segmental pointed reveal to S door. Panelled dado to nave and aisle, probably C19 but incorporating behind aisle altar some panels marked WVA 1687, said to come from former box pews.
Two steps up, beyond pulpit and Tudor arched N door to rood stair. Stone stairs in wall thickness, curving at top to upper square-headed opening, lit from rectangular light.
Broad chancel arch with two chamfers, dying into jambs, with fine oak screen (see below). Chancel floor is slightly lower, stone flagged. Ceiling of 10x8 panels. Flat heads to two S windows. Two steps to stone flagged sanctuary, with C17 altar rails and C20 altar (see below). Medieval stoup in S wall, rounded bowl and ovol-moulded triangular-headed small recess.
Fittings: Massive and crude grey stone C12 bowl font on rubble stone square platform. Fine C14 oak screen, missing rood loft. Nine bays, with wider centre opening, four openings each side with broad mid rail and panelling below. Square heads of all openings have delicate tracery to an X pattern, with cusping below and small roundels with quatrefoils in the three triangles created. The mullions between openings are moulded with a front roll and ogee sides. Top rail has vine scroll decoration. Mid C19 carved wood altar at E end of aisle in 3 panels with pierced naturalistic leaf and fruit decoration and IHS in centre roundel. C20 limed oak main altar in style of W. D. Caroe. Altar rails with thick turned balusters, barley-sugar twist on a vase pattern, and moulded rail, c1660, the gates altered. Plain C19 pews. Plain earlier C19 pulpit, five-sided with raised Tudor panels and panelled plinth, said to have been part of a three-decker pulpit.
Memorials: Nave S wall Elizabeth Griffin Williams of Bryndu died 1840 and Thomas Williams died 1848, plain marble, under stone 1820s plaques with delicate low relief detail to other family members. Chancel S wall C19 stone plaque with list of benefactors. E wall marble plaque to Rev. Charles Vaughan, died 1851, by Thomas of Brecon. Propped against n wall plaques to Mary Hopkins died 1801, and to Philip Jones died 1753, and his son died 1776, by Powel. On N wall, from E: Neo-Grec plaque with draped urn to Rev Thomas James died 1842; painted plaque with oval to Roderick Gwynne of Llyswen died 1780, by Powel of Talgarth; long plaque to John Griffin of Kington, family, and Thomas Williams of Bryndu died 1796; plaque above with winged cherub head to Benjamin Williams, died 1742, by T. Brute; large painted marbled plaque with broken pediment and arms, to Thomas Williams of Felin Newydd died 1779, by Powel; plaque with draped urn above to Thomas Williams of Felin Newydd died 1790 and his son died 1803, by Hughes; well-lettered plaque to Thomas Williams died 1730 and his wife died 1739, by T. Brute; plaque below to Philip Price of Penheoleinion died 1776, by Powel;
Stained glass: E window of S aisle has broken fragments of late medieval glass, reset 1949.