Spacious single-chamber interior with plastered walls and simple red/black quarry-tiled pavement; simple mid-Victorian pine pews flanking a central aisle. Eight-bay original roof, with 6-bay nave section and 2-bay chancel section. Of arch-braced collar truss type, with delicate, moulded trusses, modest, cusped windbraces and cusped quatrefoil and trefoil decoration above the collars. These additionally have foliated bosses to the centres. The chancel roof is canted and panelled with moulded members having foliated bosses at their junction. Crenellated brattishing to the moulded wall plate. C19 octagonal font with blind, cusped octofoils, on an octagonal base; of Cefn sandstone, a gift of the architect of the 1870 restoration. Similar pulpit with cusped and arched lights to each face, recessed in pairs, and with moulded top having foliated boss decoration; chamfered plinth and 3 steps up from the R.
The chancel is separated from the nave by a fine, original rood screen. This is of oak and has a central opening with 4-bay flanking sections, each having lights with highly-cusped heads above 5-bay arched dado sections with complex blind tracery; moulded posts and finely-carved vinescroll Rood Beam with crenellated brattishing. Surmounting this is the (rearranged) Rood Loft, with 24 niches having pierced tracery lights; brattished top surmounted by a C19 moulded beam. The chancel and sanctuary are stepped up and have simple encaustic tiled pavements by Maw and Co. Plain pine altar rails on four Gothic iron supports. Behind the altar is a panelled oak reredos with two tiers of 8 panels each. The upper ones incorporate Perpendicular crocketed canopy finials, clearly recycled from the Rood Screen canopy; crenellated brattishing to surmounting beam. On the N side of the chancel is a plain Gothic-style panelled organ; by Liddiart and Sons of Gloucestershire, early C20. Simple Victorian painted choirstalls and reading desk.
The N porch has a C16 2-bay arched-braced collar truss roof with simple chamfered detail. The N entrance is Perpendicular and has a Tudor arch with moulded and hollow-chamfered jambs with moulded label returns with carved head stops. There is evidence for extensive knife and/or sword sharpening to both jambs; C19 sunk-panel pine doors. The Vestry (former S porch) has a primary Tudor-arched N entrance with chamfered, cyclopean slatestone lintel.
Glass and Monuments: plain leaded glazing to the E and W windows, with simply-decorative glass to the nave. The S wall easternmost (nave) window has stained glass of 1889 to the Sheriff family; Adoration of the Magi. The nave N wall has 2 wall monuments to the Williams family of Bodweni, both of white and grey figured marble. That to the L was erected c1820 and has dates from 1782 to 1913; moulded top with Gothic brattishing and polychromed arms. That to the R is to Robert Williams, Esq., d.1823; segmental pediment with Adamesque decoration. The chancel E wall has a white marble classical wall monument to the Rev. Samuel Stodard, d.1788; draped urn finial with surmounting crest. On the chancel N wall is a small black and white marble tablet to the Rev. Thomas Davies, d.1825; this is signed by E J Physick of London. In the E window splay of the N chancel window is an inset slatestone benefactor's tablet; recording the gifts of John Williams of Nantffrayer, probably mid C18. Within the vestry is a wooden framed and painted funerary tablet to John Lloyd of Pale, gent., d 1742, together with a small wooden tablet to Ann Pryse, d.1781.
Within the porch is the Ceffyl Derfel (St. Derfel's Horse), a late medieval carved wooden stag, with associated turned staff or post; both have chain attachments and evidence of primary gilding and polychromy. Half of an oak panelled early C18 churchwardens' bench stands against the E wall.