St Mary's Church is a medieval building, largely unspoilt by Victorian renovation, standing upon a hill overlooking the river Kennet.
 
Services are currently in abeyance, although the church remains open.
 
See an architectural history of St Mary's Church.
See a list of rectors since 1241.
Parish registers survive from the early seventeenth century. Here is a guide to where copies can be consulted.
Ministry team

Rector                               Rev Canon Annette Shannon

Lay member                    Jenny Veasey

Churchwarden                John Stevenson

Benefice administrator  Alex King, The Barn, Enborne Church, RG20 0HD

Day-to-day management of St Mary’s is the responsibility of the parochial church council, which is elected from a roll of regular church-going parishioners. This roll is maintained by the churchwarden.
Benefice
Historically (since the thirteenth century) Hamstead Marshall was a free-standing ecclesiastical parish with its own rector. For several recent decades it has  been part of a united benefice including Enborne, West Woodhay, Inkpen, Combe and Kintbury (since 2005), within the Oxford diocese.
      The parish of St Mary's Hamstead has for several years been struggling financially, and is currently negotiating with the diocese of Oxfordand the Church Commissioiners to withdraw from the benefice and diocese, in order to be placed with either the Churches Conservation Trust of the Friends of Friendless Churches. Thanks to the generosity of a past parishioner, St Mary's has its own fabric fund, which would make it a viable acquisition for either of these charities.
      Upon being "vested" with one of these,  ownership of the church building would pass to the charity, which would ensure its upkeep. Services could still be held on request, hiring a minister, but the parish would no longer require or pay for diocesan services.
      Separate arrangements may have to be made for upkeep of the churchyard, which would not transfer automatically with the building to the recipient charity. In this case, the churchyard would remain the responsibility of the parochial church council.
      For the purposes of pastoral care ("cure of souls"), the parish of St Mary's has recently been united with St Mary's Kintbury.
Deanery and diocese
Details of the Walbury Beacon benefice can be seen on www.walburybeaconbenefice.org.uk. The benefice falls within the deanery of Newbury, which in turn comes under the suffragan bishop of Reading.
Overall, the church in Hamstead Marshall has been administered by the diocese of Oxford. (In 1836 this arrangement replaced the historic affiliation of Hamstead Marshall with the diocese of Salisbury.)
For more information on the diocese of Oxford, which also covers Oxfordshire and Buckinghamshire, see the diocesan website.