The Eparchy of Pathanamthitta is the seventh Eparchy of the Syro-Malankara Catholic Church after the event of Reunion on 20 September 1930. As per the decision of the Holy Episcopal Synod of the Syro-Malankara Catholic Church, and having consulted the Apostolic See of Rome, His Beatitude Moran Mor Baselios Cleemis, Major Archbishop-Catholicos, erected the Eparchy of Pathanamthitta bifurcating the Major Archieparchy of Trivandrum on 25 January 2010. On the same day His Beatitude Moran Mor Baselios Cleemis appointed His Excellency Most Rev. Yoohanon Mar Chrysostom, the then Bishop of Marthandam, as the first Bishop of Pathanamthitta. The inauguration of the Eparchy of Pathanamthitta and the Installation of His Excellency Most Rev. Yoohanon Mar Chrysostom as the First Bishop of Pathanamthitta was officiated by Moran Mor Baselios  Cleemis Catholicos at Cyril Baselios Catholicos Nagar (Municipal stadium) and at Sacred Heart Church, Mylapra respectively on 20 March 2010. The territory of the Eparchy of Pathanamthitta consists of five ecclesiastical districts-Pathanamthitta, Konni, Ranni-Perunadu, Pandalam and Seethathode.

This Eparchy has 111 priests, out of whom 107 are Eparchial and 4 Religious, 100 parishes, all within the territories of the civil district of Pathanamthitta. They belong to the 5 ecclesiastical districts – Ranni-Perunad, Konni, Pathanamthitta, Pandalam and Seethathode. Though the civil district of Pathanamthitta in Kerala and the Eparchy of Pathanamthitta are small in the vast sub-continent of India, this region has a privileged position in the history of India’s Evangelization. St. Thomas, one of the Apostles of Jesus Christ, preached the Good News of the Saviour and the tradition says that he established 7 Churches in Kerala and a mission station in Tamil Nadu. One of these Churches is at Nilackal (Chayal) in the district of Pathanamthitta within the boundaries of the Eparchy of Pathanamthitta. Hence, the Christians of this region are inheritors of an ancient history and patrimony. Besides the various Christian denominations, the Jacobites, the Orthodox, the Marthomites and the Pentecostals have strong communities within the boundaries of this Eparchy.

The region of Pathanamthitta enjoys a privileged position in the history of the Reunion Movement, headed by Mar Ivanios of happy memory. He made the decision of union while leading a Monastic life with his followers at Mundanmala (Ranni-Perunad) in the district of Pathanamthitta. Since his decision was in fulfillment of the ardent desire of our Lord “that all may be one,” God blessed this endeavor of Mar Ivanios, even though he had to face and overcome many obstacles. Thus, Pathanamthitta became the very cradle of the Reunion Movement. Several priests of the town and its neighborhood became zealous protagonists of the Movement. As a result of which, thousands of faithful from all Christian denominations embraced the Catholic Church. The history of the Major Arch Eparchy of Trivandrum shows that the region of Pathanamthitta is rich in priestly and religious vocations.

Reunion movement is intrinsically related to Ecumenism. Christians of all denominations now a day, show special interest in the common witnessing of the Christian faith through various means and ways. At this juncture, it is especially noteworthy that the unique ‘Ecumenical Centre’ we have in Kerala, is located at Nilackal, within the district of Pathanamthitta. The Catholic Eparchy of Pathanamthitta hosted the 62nd Reunion Day Celebrations in 2012 and on that occasion took place the dedication of the Diocesan Cathedral.

On 10th April 2018 His Excellency, Most Rev. Dr. Samuel Mar Irenios was appointed as the Co-adjutor Bishop of the Eparchy.