The Prefecture Apostolic of Assam, Bhutan and Manipur was established on 13 December 1889 with its head Quarters in Shillong and entrusted it to the Society of Divine Saviour (SDS), then known as the Catholic Teaching Society. Fr. Otto Hopfenmueller SDS was the first Mission Superior. Fr. Christopher Becker was appointed the first Prefect Apostolic of Assam on 9 January 1906. After the departure of the Salvatorians in 1915, the Jesuits from Calcutta looked after the spiritual needs of the faithful in the Prefecture until it was entrusted to the Salesians of Don Bosco on 21 July 1921. In 1934 Shillong became a Diocese, and Most Rev. Louis Mathias SDB became its first Bishop. Gradually the Dioceses of Dibrugarh (1951), Tezpur (1964) and Silchar (1969) were erected and in 1969 Shillong was made a Metropolitan See with these three dioceses as its suffragans, and Bishop Hubert D’ Rosario SDB, the Bishop of Dibrugarh was transferred to Shillong as the first Metropolitan Archbishop of North East India. Later on, more dioceses came into existence, reaching the present number of fifteen in 2006.

The Bishops of the region used to meet annually or as and when required to address various issues the Church faced and to arrive at common approaches to these issues. The beginning of the North East India Regional Bishops’ Council (shortened as NEIRBC) can be traced back to 1973. Those present were Archbishop Hubert D’ Rosario SDB (Shillong 1934), Bishop Joseph Mittathany (Tezpur 6th July 1964), Bishop Denzil D’Souza (Silchar 1969), Bishop Robert Kerketta SDB (Dibrugarh 12th July 1951), Bishop Orestes Marengo SDB (Apostolic Administrator, Tura) and Bishop Elect Abraham Alangimatthathil SDB (Kohima-Imphal 29th Jan.1973). The Meeting elected Archbishop Hubert D’Rosario SDB as Chairman of the NEIRBC and Bishop Denzil D’ Souza as its Secretary.

The diocese of Imphal was erected on 21st April 1980 bifurcating from the diocese of Kohima-Imphal. In the year 1983 on 5th December, the Diocese of Diphu was erected detaching it from the Archdiocese of Shillong-Guwahati. The diocese of Guwahati was erected on August 16, 1992 carved out of the Archdioceses of Shillong, Tura and Tezpur. The diocese of Agartala was erected on 11th January 1996 bifurcating it from the then known diocese of Silchar. On 10th May 2000 the diocese of Bongaigaon was erected bifurcating from the Archdiocese of Guwahati. The diocese of Itanagar was erected in 2005 detaching it from the care of the diocese of Tezpur. In the same year 2005 on the same day ((December 7) for the East Arunachal the diocese of Miao was erected bifurcating it from the diocese of Dibrugarh. On 28th January 2006 the dioceses of Jowai and Nongstoin were erected bifurcating from the Archdiocese of Shillong.

In the year 1995 Guwahati and Imphal were made the Metropolitan sees. Accordingly Dibrugarh, Tezpur, Diphu, Bongaigaon, Itanagar and Miao became the suffragans of Guwahati Metropolitan with Archbishop Thomas Menamparampil SDB; while Kohima as suffragan of Imphal Metropolitan with Archbishop Joseph Mittathany were declared. In the meantime with the Shillong Metropolitan Tura, Aizawl, Agartala, Jowai and Nongstoin remained as suffragan dioceses.

All the fifteen (15) Diocesan Bishops of North East India and the Auxiliary Bishops along with the Emeriti Bishops and those who are equivalent to them in law constitute the NEIRBC. For over 40 years the NEIRBC has been meeting twice a year – April and September. With a view to empower the NEIRBC and its Commissions, Offices, Departments, Cells and Apostolates more effectively in the year 2015 a permanent office of NEIRBC was established at the INSPIRATION Building, near North East Diocesan Social Forum, at Joypur, Kharghuli, Guwahati – 781004, Assam with the fulltime resident Deputy Secretary in the person of Fr. G.P. Amalraj (Diocese of Dibrugarh). Presently in the Inspiration building the following offices of NEIRBC are located viz. Office of the Deputy Secretary General, North Eastern Education Commission (NEEC), North East Social Communications (NESCOM), North East Regional Youth Commission (NERYC), Commission for Ecumenism, Women Commission and Assam Catholic Education Trust (ACET).