Before September 1987, the area which is now Mymensingh Diocese was part of Dhaka Archdiocese. So the early history of the Church in this Diocese is linked up with the history of Dhaka. In the second part of the 16 th century, there were already Catholics in various parts of what is now Mymensingh Diocese, such as at Hoshenpur of Kishorganj District. But the remarkable Catholic evangelization work among the Garo people began only in the early 20 th century. This work among the Garos and the progress made is indeed a bright spot in the history of the Church in Bangladesh. In 1909, five Garo leaders made the long trip down to Dhaka to ask the Catholic Bishop to send a priest. A year later, the Bishop sent Fr. Fleury, CSC, and Brother Eugene, CSC, to study the situation. In late 1910 and early 1911, Fr. Adolphe Francis, CSC, began the work in Tausalpara near Ranikhong. On 19 March 1911, Father Francis reaped the first fruits with 21 Catholic baptisms at Tausalpara. The first church among the Garos was built at Tausalpara in 1912, and in 1913 Fr. Francis began living there. In 1915, he moved to the Ranikhong Hill where Ranikhong Parish is now. Until 1918, Father Francis was practically always alone, tramping the Garo country from east to west, covering the 90 miles strip of territory, where in the following twenty-five years a total of six parishes were established.

When the Mymensingh Diocese was created in 1987 (comprising the Civil Districts of Mymensingh, Jamalpur, Kishorganj, Netrakona, Sherpur and Tangail), eight parishes existed: six of them close to the Indian State of Meghalaya border (from East to West): Baluchora (1930), Ranikhong (1912), Bhalukapara (1926), Biroidakuni (1928), Baromari (1942) and Mariamnagar (1937). Parishes had also been established in Mymensingh Town (1927), and at Jalchatra (25 miles Southwest of Mymensingh Town in 1960). Three additional parishes (bringing the 2007 total in the Diocese to 11 parishes) have since 1987 been erected at Boruakona (1989, with territory taken from the eastern part of Baluchora Parish), Pirgacha (1993, with territory taken from the northern part of Jalchatra Parish), and Joljolia (2006, with territory taken from the western part of Biroidakuni Parish).

On May 15, 1987, Pope John Paul II erected the Diocese of Mymensingh and named as first Bishop, Fr. Francis Anthony Gomes, who was then studying in Rome. On September 8, 1987 the new Diocese was officially erected, and the new Bishop was consecrated in Mymensingh. On Christmas Day 2003, Father Ponen Paul Kubi, CSC (at the time Director of the Pobitra Krush Sadhana Griha, Rampura, Dhaka) was appointed Auxiliary Bishop of Mymensingh and consecrated in Mymensingh on 13 February 2004. On 15 July 2006, Bishop Ponen Paul Kubi, CSC, was appointed Second Bishop of Mymensingh by His Holiness Pope Benedict XVI. The Installation ceremony was held in September 1,  2006.