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. From 1937 onwards priests began to take permanent residence at Mariamnagar. The first Parish in Tripura was erected at Mariamnagar in 1939. The first permanent Church 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 with Most Rev. Denzil D' Souza, DD, as the first Bishop of Silchar, which comprised the states of Mizoram and Tripura and the District of Cachar in Assam. 

By the Papal Bull "Venerabiles Frates Nostri" dated January 11, 1996, Pope John Paul II decreed the erection of the Diocese of Agartala. The new Diocese of Agartala which comprises the entire state of Tripura 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 with St. Francis Xavier as the Patron. The motto is "Lead us Onward".

Today the Diocese of Agartala has 20 Parishes and a Catholic population of over 45,000 in total of 3.7 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: Debbarma, Reang, Darlong, Halam, Garo, Jamatia, Tripura, Molsom, Rupini, Kaipeng, Hrangkhawl, Bongcher, Mog, Munda and Santhal.