Tower has high plastered shallow curved ceiling, possibly stone vault. Small pointed door to N stair, pointed plastered arch to nave. Four-bay arcade in grey stone, 2 bays to nave and 2 to chancel, of roughly cambered arches on round piers with plain chamfered caps and bases. Pier between is chamfered towards aisle and has similar cap and base. Painted plastered walls, plain pointed plastered chancel arch. All roofs of 1892, boarded with arch braced collar trusses on stone corbels, the collars and wallplates ornamented with brattishing.
Fittings: In chancel arch each side a large carved head corbel, male with a circlet around hair and a female, both much restored and presumably reset. C12 rectangular large scalloped font with darts between scallops, on round shaft with moulded base. Mid C20 oak pulpit with Gothic blind tracery panels. Nave simple pine pews and chancel stalls of 1892, earlier painted grained pews in aisle. Painted grained simple Gothic open rails on both W and S sides of sanctuary.
Stained Glass: Nave N first window Lamb of God 1997 by Celtic Yard, third window by same, St Francis, 2001. S aisle: SS Catherine, Michael and Leonard, to William and Martha Owen of Withybush, early C20 by R.J. Newbery. E window has mid C19 coloured patterned glass with painted glass IHS monogram in sunburst and Gothic foliate motifs in upper sexfoil.
Monuments: Nave N: large inscribed slab to David James of Roswell (d 1767); Patrick Clement (d 1835) pedestal-type plaque by D. Lloyd of Nevern; Thomas Phillips of Kilbarth (d 1828) and wife (d 1840), plaque by J. Thomas of Haverfordwest. Chancel floor slabs to Jane Hayward (d 1699) and Maj. Gen. John Picton of Poyston (d 1815). Chancel N wall metal plaque to W.S. Owen of Withybush (d 1909); Martha H. Owen (d 1885); William Owen, the noted Haverfordwest architect (d 1879), plaque by Currie of Oxford St; Hannah Scott (d 1798), tall neo-classical plaque with urn and scroll sides; Samuel Phelps (d 1827) neo-Grec plaque with urn; C20 brass plate to Archbishop William Laud; plaque to Thomas Picton of Poyston (d 1790), his wife (d 1806) and daughter (d 1830); twin slate memorials to Thomas Picton and John Picton, (both d 1727) with low-relief skulls in corners and oval plaques; slate plaque to Eliza Warren (d 1789).
Howard or Hayward of Fletherhill family memorial filling E wall of S aisle, monumental scale. Three recesses with full length figures bearing skulls, well-carved and splendidly dressed, James (d 1668) and Joanna Howard in centre, George (d 1665) to left, and Thomas (d 1682) and Mary (d 1685) to right. Outer recesses are arch-headed, centre has 3-sided head. Carved leaf sprays in spandrels, cornice and swan-neck pediment with armorial cartouche.
S aisle S wall: Rev. J. Owen (d 1907) metal plaque; William Meredith (d 1770) grey and white marble with broken pediment and urn; G.L. Owen (d 1905) brass plaque; General William Picton (d 1811) plaque in black frame with triangular white marble head, inscription relating military career including service at siege of Gibraltar 1782; Henry Owen (d 1909), brass plaque; Major-Gen John Picton (d 1815), white marble with crudely carved lion over, against top part with oval shield and standards; long slate plaque with small marble urn and scrolls to Lt J. Warlow (d1827) and mother (d 1832). W wall recess in blocked window with plaster copy of 1816 S. Gahagan bust of General Sir Thomas Picton, and plaque of 1907 recording his death at Waterloo, 1815, and burial in St Pauls Cathedral, London. S aisle N: Jane Griffiths, servant at Poyston, (d 1814), stone reeded surround.