The church of St. James, Heyshott, consists of chancel with north vestry, nave with western bell cot, north aisle and south porch; it is built of flint rubble with ashlar dressing and is roofed with tile.
 
In the 13th. century it consisted of chancel, nave and narrow north aisle; in the 19th. century the chancel was rebuilt; the aisle widened and the porch added; and the vestry added in the 20th. century.
 
The church of Heyshott was presumably founded as a chapel to that of Stedham; It was so styled in 1291 and it continued attached to Stedham until 1882, when it was constituted as independant rectory in a gift of the Bishop of Chichester. The church registers begin in 1690.
 
The chancel has diagonal eastern buttresses in two stages of offsets; in the south is a three light window with segmented arched head of perpendicular tracery, in the north is a single lancel now covered externally by the vestry, and the plain pointed doorway leading to the latter; the roof has a single truss with principlas, collar king posts, diagonal struts. The chancel arch, also modern, is of two orders, pointed, with square responds and corbels to carry the inner order, in the English style.
 
The nave has one buttress at the south east corner; and intermediate one at the south-side, a pair at the south-west corner and a single one at the north-west. These are all of two stages with sloping offsets and appear to be 13th. century. In the south wall is a window or two trefoil headed lights with semi-perpendicular tracery, perhaps 14th. century, but much restored, the south doorway is a plain pointed arch of one order with a segmented rear arch, perhaps 13th. century. The north arcade of three bays, has pointed arches of two orders resting on two cylindrical piers with moulded capitals and bases; the later are partly covered by the present floor, the former have abaci of romanesque rather than the gothic profile, but are probably of 13th. century, and the east respond is in the form of a half-pier, the west is square, the arch dying away into the west resembles the south. There are four ancient roof trusses; the two eastern tie-beams each are braced with king posts supporting a collar purlin, the two western carry lengthwise timbers supporting the bell cot, the under side of the rafters are ceiled with plaster, the sides are boarded and the pyramid roof shingled.
 
The north aisle is modern: the east and west windows are copies of the west window on the nave, in the north are three lancet windows. In the mid-most of these are four scraps of ancient stained glass which is yellow stained perhaps in the 15th. century, who had done repair work at the church in 1855. Mrs. Fisher Unwin had these replaced in the window in 1912.
 
The uppermost glass shows a mitred head with long hair, the next is the upper part of an angel playing on cymbals, and the lowest, an angel playing on a crowd. The spanned roof is on three bays with trusses like those of the chancel.

 
The south porch - [modern] is a plain building of stone. The font is a single block, its upper part is tube shaped, its lower formed into four capitals, perhaps originally 12th. century, later adapted to be set in five shafts, but now resting directly on a plain base.
The cover is of oak of 17th. century. The other fittings are modern.
 
When pews were being removed because of dry-rot in the south side of the nave, stone covering was removed and an old piscina with a drainage hole was discovered, this has been left open to view. Mr. S. Parry was carrying out this work.
 
The church-yard has been enlarged to the north and now encloses the grave of a local highwayman.
This ground was consecrated by the late Bishop Bell of Chichester.
 
James Allen, a deserter, who shot and killed Capt. George Sargent, Squire of Lavington was buried here in 1807.
His grave is in the south-east corner of the church-yard.
 
In the south wall of the nave is a stained glass window to those who gave their lives in the 1914-18 war, their names are in the glass panels at the base, and a stone plaque is on the cill with the names of those who gave their lives in the 1939-45 war.
 
1914-1918
Edmund Batchelor, Frank Bear, Ernest Boswell, Basil Ralph, Wm. Frank Daughtry, Isaac Ellcome, Walter Miles,
William Lockyear, Frank Sinkin, Gilbert E. Smith, Jethrow West, Herbert Wrapson, George Honeybun.
 
1939-1945
A. Annetts, W.E. Buck. C.F.G. Cockerell, A.A. Ford,
Wm. Fitz-Simon, John Lockyear, D.M.J. Murray, G.R. Pim, E.A. Prior.
 
There is a plaque to Richard Cobden [1804 - 1865] at the end of the pew on the south wall of the nave.
 
Over the south door there are the arms of King George I. II. and III. 1714-1800.
 
The Reredos, a plaster cast, which was above the alter, partly covering the east window, had gilded figures of Christ and two Seraphim. The Reredos has now been removed together with the two anodized metal plaques which were fixed on the wall each side of the east chancel window. The Lord's prayer was written on the left and the Commandments on the right side.
 
The church organ was installed in Rev. C.W. Lyne's time [1913-23] and was located in the south-west corner of the nave. It was pumped by hand, by boys for 1d. for each service until an electric pump was installed in 1957. Mice and wood worm attacked the black notes of this organ and it was replaced with another organ in 1972 which was re-sited at the west end of the north aisle.
 
The brass lectern was given to the church by Miss Pope and the alter rail was carved from oak by Mr. Stephen Parry, the village wheelwright in approximately 1900.