The church consists of an aisled nave with a clerestorey and a massive S porch, an aisleless chancel with N vestry, and a W tower. Construction is largely of flint and pebble rubble, although the tower is rendered. Of this, everything except the nave aisle W windows and doorways and the piscina, which are 14thc., belongs stylistically to the early 15thc., and must represent the church erected in 1387, at the sole cost of Thomas Patesle, then vicar, who is buried in the nave. The tower is square in its lower storey and octagonal above, with a stumpy lead spire, but this form is not original. The medieval tower collapsed in 1798 and was rebuilt to this design using old materials. At the same time the nave seems to have been reduced from its original five bays to the present four. The only Romanesque features are carved stones, presumably from the pre-Patesle church, arranged to form a niche above an altar.

In 1086 Great Shelford was substantially held by the Abbey of Ely. Nine hides and 24 acres were directly held by the abbey. Hardwin (de Scales) held 2½ hides and 9 acres and a minster of the demesne farm of the monks of Ely. Seven sokemen held 1½ hides and 6 acres from the abbot. In addition the king had holdings here in the form of a berewick of his farm at Newport (Essex). These 3 hides were held from the king by Peter de Valognes.

The sawtooth stones (5.c.(vii) and (viii)) probably came from a string course similar to the one at nearby Haslingfield.