Catholic Diocese of Kitui is found in the ecclesiastical region of Kenya and it is within the Nairobi metropolitan. It covers the whole Kitui County which is comprised of the following districts: Kitui West, Kitui Central, Lower Yatta, Nzambani, Mutitu, Mwingi Central, Mwingi West, Mwingi East, Kyuso, Mutomo, Mumoni, Tseikuru, Katulani, Mwingi West, Matinyani, Kisasi and Ikutha. It is an arid and semi-arid area of approximately 30,496.4 sq. Kms in Eastern Kenya, with a population of around 1,012,709 people according to 2009 census statistics. The Diocese has over 240,000 baptized Catholics.
The first Missionaries to evangelize Kitui were Holy Ghost Fathers from Kabaa (Machakos) in early 1930s. Also, by the time the Holy Ghost Fathers were introducing Christianity in Kitui, the Consolata Missionaries from Meru were evangelizing in the northern region of Kitui (now Kimangau). The first Mission house was built in 1945 at Mutune. Kitui Apostolic Prefecture was curved from the Archdiocese of Nairobi in 1956 under care of St. Patricks Kiltegan Missionaries, later being erected as a Diocese in 1964, with His Lordship, the late Rt. Rev. William Dunne as the first Bishop. The first Diocesan Priests in the Diocese were Frs. Peter Muema Kyumbua and Late Boniface Lele, who were ordained in 1974. The first nun to profess was Sr. Teresia Muli (Assumption Sisters of Nairobi) from Boma.
Following his retirement in 1996, the late Rt. Rev. Boniface Lele succeeded him, until he was appointed the Archbishop of Mombasa in 2005. The Diocese was overseen by a Diocesan Administrator until May 2007 when Rt. Rev. Bishop Martin Kivuva was appointed as the Apostolic Administrator. In 2008, Rt. Rev. Anthony Muheria was appointed the Bishop of Kitui Diocese.
The Diocese consists of four Deaneries: Northern Deanery with 10 Parishes, Central Deanery with 7 Parishes, and Southern Deanery with 5 Parishes and Eastern Deanery with 4 parishes. In 1989 there were 16 Diocesan priests and their numbers grew to 30 in 1999. Currently there are 82 Diocesan Priests, 2 Retired Missionary Priests working in the Diocese. There are 32 Seminarians in the various seminaries. There are also 12 congregations of Religious men and women serving in the Diocese; with Daughters of Jesus the Good Shepherd (DOJGS) as a Diocesan congregation.