The church has a W tower, and a nave with 14thc. N and S aisles of three bays now, but originally longer - the aisles have been removed and the arcade blocked at the W. There are N and S transepts and an aisleless chancel the same width as the nave's central vessel. Construction is of flint with a brick chancel and buttresses of brick with ashlar facings. The church has seen extensive rebuilding in brick. The tower has three storeys of which the first and most of the second are flint, while the top part of the second and all of the third has the flint loosely chequered with ashlar blocks. The font is the only 12thc. feature.

As is the case with many Cambridgeshire villages, the Domesday Survey reveals that Croydon was parcelled into small holdings. The largest in area and value, consisting of 3 hides and 1 virgate, was held by three men-at-arms under Hardwin de Scales. Humphrey held 2 hides from Eudo fitzHubert. Ansketel held 2 hides less half a virgate from Picot. Earl Roger held 3 virgates himself, and of Count Alan's holding in the village, 2½ virgates were held from him by Aelmer and 1 virgate by Fulchei. No church is mentioned at that time. In 1092 Picot granted ? of the tithes of this and other manors held by his knights for the foundation of Barnwell Priory.