File:Caistor, Ss Peter & Paul church, interior (26958748195).jpg

The church dates from the 11th century onwards and was rebuilt and restored in the 19th century. Certainly there was a church here in Saxon times and the lower part of the tower is probably Saxon, from around 1050. There is a west tower, nave with clerestory and north and south aisles, north porch, vestry and chancel. The tower is built in ironstone and dates from the mid-12th century. It is thought that the lower stage the tower could have been a Norman porch to the old church. The second stage is Early English and the top stage is Perpendicular. The tower has an embattled parapet with pinnacles and gargoyles. The tower arch has zigzag decoration. There are eight bells.

The nave has four-bay arcades with octagonal piers and four clerestory windows either side. The chancel arch is from the 13th century. It is thought that the church may have been intended as being a cruciform shape with a crossing, or it may indeed have once been like this.

The chancel was largely rebuilt in 1848 and restored in 1873. The reredos is from that date.

There are several effigies of Knights set into arched tombs in the wall.

There is a triple lancet east window, and stained glass from a variety of makers. The organ is by Cousans, and was installed in 1885. The rood beam is by Wilfrid Bond, erected in 1929.