St Mary's Church is a medieval building, largely unspoilt by Victorian renovation, standing upon a hill overlooking the river Kennet. The congregation is small but friendly, and welcomes all-comers to services, which are held two or three times a month.
The church is open at service times and also at times of special religious significance (as indicated by a "church open today" sign outside). At other times visitors may gain access by contacting one of the churchwardens for a key. The locking-up of the church is greatly regretted, but it was made necessary by a series of burglaries some years ago.
The ecclesiastical parish of Hamstead Marshall has since 1981 been part of a united benefice which also includes Enborne, West Woodhay, Inkpen and Combe. Since 2005 this benefice, and the separate benefice of Kintbury with Avington, have been jointly served by one rector. Details of the Walbury Beacon benefice can be seen on www.walburybeaconbenefice.org.uk