The Catholic Diocese of Oyo was carved out of the Catholic Archdiocese of Lagos. Hitherto, Priests had to come all the way from Lagos, Ibadan and even Ijebu-Ode to celebrate the Eucharist in Oyo and its environs. As at the time, only the stations like Oyo, Osogbo, Otan, Inisa, Ilesa etc, were mainly the beneficiaries. Priests were later stationed in these towns.
In April 1949, the old Oyo province-excluding Ibadan was erected as the prefecture of Oyo. The white-fathers (the Missionaries of Africa) were invited to take charge. Fr. Owen McCoy who later became the first Bishop of Oyo (now deceased), led a group of some White-Fathers to start the work of evangelization in the area.
On 1st March, 1963, the prefecture of Oyo was raised to the status of a Diocese, with the prefect Apostolic, Rt. Rev, Msgr. Owen McCoy, becoming the first Bishop of Oyo till his retirement in 1971.
In 1971, Rev. Fr. Anthony Olubunmi Okogie of Lagos Archdiocese was ordained Auxiliary Bishop of Oyo Diocese, remaining so until the death of Archbishop J.K. Aggey of Lagos Archdiocese, when he was moved to Lagos as Archbishop. The vacancy was thus created in Oyo Diocese which was filled by calling on Rev. Fr. Julius Babatunde Adelakun to take over as Bishop of Oyo Diocese on 11th February, 1973.
On 14th March, 1995, the Diocese of Osogbo was carved out of Oyo Diocese with its headquarters at Osogbo. Thus the new seat of Bishop of Oyo was transferred to Oyo town. The liturgical ceremony marking the canonical installation of the Bishop of Oyo at his new seat was held on 30th April, 1995 at the church of Our Lady of the Assumption, Oyo now raised to the status of a Cathedral.
The Diocese of Oyo made history as she received the good news of appointment on August 14, 2007 of the Co-adjutor Bishop for the Diocese, in the person of Rt. Rev. Msgr. Emmanuel Ade Badejo. The celebration of his Episcopal ordination took place on 20th October, 2007, at St. Francis Catholic College, Oyo. Most Rev. Emmanuel Ade Badejo was born on the 13th July, 1961. He was ordained a Priest on the 4th January, 1986. The Co-adjutor Bishop worked with the Diocesan Bishop in looking after the spiritual welfare of the Diocese.
Most Rev. Julius Babatunde Adelakun remained the Bishop of Oyo till his retirement on the 4th November, 2009 while the canonical installation of Most Rev. Emmanuel Ade Badejo as Bishop of Oyo took place on 20th November, 2009.
The Diocese of Oyo is some 18,000sq.km in size. It is situated in the Yoruba South West area of Nigeria and occupies a larger part of Oyo State covering Oyo, Ogbomoso and the whole of Oke-Ogun. The Diocese is bounded in the North by Ilorin Diocese, in the South by Ibadan Archdiocese, in the East by Osogbo Diocese, in the South West by Abeokuta Diocese, and in the North West border area by some of the Dioceses of the Republic of Benin. The total population is two and a half million of which only 36,432 are Catholics.