Tura was made a diocese on April 7, 1973, by detaching territories from the Archdiocese of Shillong - Guwahati. The diocese comprises East and West Garo Hills districts and the part of Goalpara district south of Brahmaputra River.

Bp Orestes Marengo sdb, former Bishop of Dibrugarh and later Bishop of Tezpur from which he resigned in 1969, was appointed Apostolic Administrator of Tura. The Holy Father relieved Bp Marengo of the office of Apostolic Administrator of Tura on February 8, 1979 and appointed Bp George Mamalassery of the Diocesan Clergy as the bishop.