The beginning of the Catholic faith in Tripura dates back many centuries. Fr. Ignatius Gomes, a Jesuit priest made the first reference to the Christians of Mariamnagar in Agartala when he visited them in 1683. Fr. P. Barbe, the Pastor of Chittagong, visited Tripura in 1843. Holy Cross pioneering missionaries Fr. Louis Augustine Verite and Fr. Beboit Adolphe Mercier visited Agartala in 1856 and administered sacraments to the Christians in Mariamnagar Village. But it was only from 1937 that priests began to take permanent residence at Mariamnagar. The first Parish in Tripura was erected at Mariamnagar in 1939. The first permanent Church (at present the temporary Cathedral) was blessed in 1952. Because of its geographical proximity, the Archdiocese of Dhaka continued to cater to the spiritual needs of the Catholics in Tripura till the erection of the new Ecclesiastical Unit in 1952, namely, the Prefecture of Haflong. In 1969, the Prefecture was upgraded to the position of a Diocese and Most Rev. Denzil D'Souza, DD, was the first Bishop of Silchar. At that time the Diocese comprised the States of Mizoram and Tripura and the District of Cachar in Assam.

By the Papal Bull VENERABILES FRATES NOSTRI dated 11th January 1996, Pope John Paul II decreed the erection of the Diocese of Agartala. The new Diocese of Agartala, comprising the entire State of Tripura, with 11,000 Catholics in 9 Parishes was bifurcated from the erstwhile Diocese of Silchar. Most Rev. Lumen Monteiro, CSC, DD, was appointed the first Bishop of the new Diocese. He was ordained and installed on May 26, 1996. The Diocese of Agartala is dedicated to Christ the Light of the World. St. Francis Xavier is the Patron of the Diocese. The motto of the Diocese is DUC IN ALTUM = LEAD US ONWARD.

Today the Diocese of Agartala has 20 Parishes and a Catholic population of 40,000 in total of 3.6 million people. The Diocese of Agartala which comprises the entire State of Tripura with 8 Civil Districts has 30% of its population comprising of the indigenous tribal people who come from 19 major tribes. To mention a few: Reang, Debbarma, Darlong, Halam, Garo, Jamatia, Tripura, Molsom, Chakma, Hrankhawl, Bongcher, Mog, Kuki and Lusai. The majority population is non-tribal.