St Andrew's has a low, five-bay nave with 13thc. aisles of slightly different designs, and no clerestorey but big, Perpendicular aisle windows. The 13thc. chancel is aisleless and has a 19thc. E window in a Perpendicular style. There is a late-13thc. W tower without a spire. Construction is of pebble rubble on an ashlar plinth course except for the chancel where a good deal of coarse, dark brown conglomerate is used. The E wall of the chancel is rendered. The only Romanesque feature is the font.
The Abbot of Crowland held seven-and-a-half hides in Oakington in 1086. Roger held 1½ hides from Countess Judith, and the wife of Boselin de Dives held 1½ hides, which were given to her by the Bishop of Bayeux, 'but the men of the hundred do not know on what grounds'. Aelfgat the Priest held 15 acres from the Abbot of Ely. Something under 4 hides were held by three knights of Picot of Cambridge, and in 1092 Picot granted ? of the tithes of this and other manors for the foundation of Barnwell Priory. By the 1190s Oakington was one of three Cambridgeshire parishes whose rector was presented by Crowland Abbey, Lincs.
At W end of S aisle, a square, arcaded 12thc. bowl mortared onto a later medieval support (five octagonal shafts with high moulded bases but no capitals, supporting a chamfered block). The arcading is irregular with three bays on the E and N faces and two bays on the S. The W face is plain, so the font was probably sited against a wall originally. The arcades are of stilted semicircular arches with ovals for capitals. At each angle of the bowl is a roll treated as a shaft with a cushion capital. The basin is circular with a lead lining and there are mortar repairs on the rim.
|ext. h. of bowl||0.46 m|
|ext. w. (E-W)||0.705 m|
|ext. w. (N-S)||0.705 m|
|int. diam. of bowl||0.535 m|