The Roman Catholic Diocese of Khamman  is a diocese located in the city of Khamman in the Ecclesiastical province of Hyderabad in India.

The diocese of Khammam was bifurcated from the ecclesiastical jurisdiction of Warangal diocese by the Papal Bull ad "perpetuam rei memoriam" on February 11, 1988. It comprises the entire revenue district of Khammam. Most. Rev. Joseph Rajappa was appointed as the first Bishop of Khammam diocese. The Christian faith in this area has a century old history.

The Mission work was actually launched by the PIME missionaries much before 1885 when this area was under the Hyderabad vicariate. The oldest Catholic Community brought to faith by Fr.F.Rolla PIME in 1905 still remains as a historical monument. Msgr. Vigano's Pastoral visits to different places could also bring some impact in the Christian communities. Because of their strenuous efforts, we could now have the pride of having Bayyaram parish because the first one to yield the first vocation in the diocese and later five more.

The Diocese of Warangal was bifurcated from the Ecclesiastical territory of Hyderabad as a separate diocese, comprising the districts of Warangal, Khammam, Karimnagar and Nalgonda by Pope Pious the XII on December 22, 1952. Most Rev. Alphonsus Beretta PIME was the first Bishop of Warangal. On 8th January 1953, under the dynamic leadership and great vision of Bishop A. Beretta, the Catholic Church in Khammam penetrated into interior places. Bishop Beretta set up many schools, dispensaries, boardings and launched other socio-economic developmental schemes. He invited several religious congregations to work in the rural belt of Khammam. In 1985 Bishop A. Beretta PIME retired and in1987 bishop Thumma Bala was appointed as the second Bishop of Warangal. Before he could realize his plans, Khammam district was declared as a diocese in 1988. Bishop Joseph Rajappa was appointed as the first Bishop of Khammam. Unfortunately he died on the following year i.e. 27th December 1989 due to old age and illness. The diocese was administered for a couple of years by Rev.Fr.M. Lourdunathan. On January 31, 1992, Fr.Marampudi Joji, of Vijayawada diocese was appointed as second Bishop of Khammam. After four and a half years, he was transferred to Vijayawada on December 18, 1996. Rev. Fr. D. Melchior Raja, PIME, administered the diocese for a couple of months. On May 30, 1997, Fr. Maipan Paul of Visakhapatnam diocese was appointed as the third Bishop of Khammam.