The Syrian Catholics, mostly the Syro-Malabar Catholics, from various parts of Kerala had started migrating to different areas of Tamil Nadu years back, i.e., in the first half of the 20th century, for the purpose of job, business etc. The Syrian Catholics who thus came in the beginning were going to the churches of the Latin Rite for fulfilling their spiritual needs. But as the territory of the undivided eparchy of Trichur was extended on 29th April 1955 to the areas of Tamil Nadu, co extensive with those of the diocese of Coimbatore they got opportunity to get their spiritual needs fulfilled according to their own Mother rite. It was the late Mgr. Zacharias Vazhappilly, the Vicar General of the eparchy of Trichur at that time, who was appointed to coordinate the pastoral care for the Syro-Malabar migrants in this area. Under the leadership of Mgr. Zacharias a team of priests and religious who were zealous, dedicated and hardworking continued their pastoral care.

Eventually the number of migrants increased and it led to the arrangement of more infra-structures as the part of the pastoral coordination. In that way, the first Forane in this area, i.e., Coimbatore Forane was formed centralizing Ramanathapuram, in the Month of November 1973. Coimbatore forane comprised of all the parishes and stations in the extended area of Tamil Nadu of the eparchy of Trichur. It was a milestone in the history of the pastoral care of the Syro Malabar migrants and the erection of the eparchy of Palghat.

The Eparchy of Palghat was erected on June 20, 1974, through the Decree "Apostolico Requirente", bifurcating the eparchy of Trichur. It was a suffragan of the Archdiocese of Ernakulam. The eparchy was inaugurated on September 8, 1974. The episcopal ordination of Msgr. Joseph Irimpen and his assumption of office as the first bishop of the eparchy took place on the same day. It is now a suffragan of the Archdiocese of Trichur.

The Lord has done great things for the people of God of this area through the pioneering and missionary work of the priests, sisters and the laity under the able and inspiring leadership of Mar Joseph Irimpen. After twenty years of dedicated and loving service Bishop Irimpen retired from his office on December 6, 1994. He slept in the Lord on August 23, 1997. Msgr. Joseph Veliyathil served the Eparchy as its Administrator from December 6, 1994 to February 1, 1997. Pope John Paul II nominated Bishop Jacob Manathodath, the then Auxiliary Bishop of Ernakulam-Angamaly as the Bishop of Palghat on November 11, 1996. Bishop Manathodath took canonical possession of the eparchy on February 1, 1997.

In the light of the application of His Excellency Mar Jacob Manathodath, the Bishop of Palghat, the XVIth Synod of Bishops of the Syro-Malabar Church held at Mount St. Thomas, Kakkanad in August 2008, unanimously gave its approval for the erection of the eparchy of Ramanathapuram. Thus, after due consultation in the Synod of Bishops and having obtained its consent and the assent of the Apostolic See, and having fulfilled everything required by law, as per the decree of 18th January 2010 with Prot. No 57/2010, His Beatitude Mar Varkey Cardinal Vithayathil, the Major Archbishop of the Syro-Malabar Church, by virtue of the authority vested in him and in accordance with CCEO c. 85#1, erected the Eparchy of Ramanathapuram, bifurcating the eparchy of Palghat. Thus the new eparchy has its territory comprising the four civil districts of Tamil Nadu namely, Coimbatore, Erode, Karur and Tirupur and its See in the City of Ramanathapuram in the civil district of Coimbatore. Fr. Paul Alappatt, a priest from the Archeparchy of Trichur was appointed as its first Bishop the same day (Prot. 58/2010). He was ordained bishop by His Grace Mar Andrews Thazhath, the Metropolitan Archbishop of Trichur, on the White Sunday, the 11th April 2010 at Ramanathapuram (Alvernia school ground). His Grace Mar Jacob Thoomkuzhy, Archbishop emeritus of Trichur and His Excellency Mar Jacob Manathodath, Bishop of Palghat were the co-consecrators in the Ordination ceremony. The eparchy was inaugurated the same day. About 12,000 faithful including bishops, civil dignitaries, priests, religious and laity were present on the occasion.