The Cathedral Church of SS Peter & Paul, Dyfrig, Teilo and Euddogwy is the mother church of the Diocese of Llandaff and is the seat of the Bishop of Llandaff. The Diocese, one of the six dioceses comprising the Province of The Church in Wales, covers the general area of South Wales bounded by Cardiff in the South East to Neath in the South West, the Heads of the Valleys to the North and the Rhymney Valley to the East.
The Cathedral also serves as a Parish Church, the Dean also being the Vicar of the Parish of Llandaff.
The Cathedral lies close to the bank of the River Taff in the ancient "City of Llandaff" much of which is now a conservation area. Despite being surrounded on all sides by the bustling modern city of Cardiff, the Llandaff conservation area remains comparatively unspoilt and surprisingly tranquil.