The Diocese for The Malankara Orthodox Church was formed for the first time in 1876 after the Mulanthuruthy Synod. Then H. H. Patriarch Mar Peter III divided the Malankara Church in to seven Dioceses - Ankamali, Cochin, Kandanad, Kottayam, Niranam, Thumpamon and Quilon (now Kollam). In 1953 Malabar Diocese was formed. In 1938 Diocese for outside Kerala was formed and in 1976, the outside Kerala Diocese was divided in to three namely Bombay Madras and Delhi dioceses. Also Malabar diocese was enlarged adding certain areas of Tamil Nadu. On 30th October 1978, three new dioceses – America, Calcutta and Trivandrum were recognized. In 1982 Idukki Diocese was formed by taking out high range areas from Kottayam Diocese. In 1985 Chengannoor Diocese was formed by grouping 50 Churches out of Thumpamon, Niranam and Kollam Diocese and same year Kunnamkulam Diocese was formed by dividing Cochin Diocese. Also Sultan Bethery Diocese was formed by grouping Churches from Vayanadu, Canannore, Coorg and Nilgiris from the Malabar Diocese in the same year. On 1st August 1993, Canada-UK-Europe Diocese was formed by grouping 8 Churches from Delhi diocese and 8 Churches from America Diocese. In 2002, Mavelikara Diocese was formed by grouping 50 Churches out of Thumpamon, Niranam and Kollam Diocese and same year Trissur Diocese was formed by dividing Cochin and Kunnamkulam Diocese. The same year, Kandanadu Diocese was divided in to Kandanadu East and Kandanadu West. In 2009, South West American Diocese was formed by grouping 40 Parishes from American Diocese and a new Diocese of UK, Canada, Africa was formed with 18 Parishes. Bangalore and Ahmedabad diocese with 28 parishes and 35 parishes respectively were also formed in 2009. Thus our church has total 25 dioceses with 16 dioceses in Kerala and 9 dioceses outside Kerala.

History of Chennai Diocese:

Former Diocese of Madras was consisted of present Calcutta and Madras dioceses with H.G. Dr. Stephanos Mar Theodosius as the first diocesan Metropolitan. Present diocese of Madras was formed on 1979 with the territorial area of Tamil Nadu, Karnataka, Andhra Pradesh and Andaman island in India, Australia, New Zealand, Malaysia, Singapore and churches in far east countries and the diocese Metropolitan was late H.G. Zachariah Mar Dionysius. Following the formation of Bangalore diocese in 2009, the parishes from Karnataka and Andhra Pradesh are moved under Bangalore diocese and Chennai diocese now have 39 parishes.
Since the solemn demise of H.G. Mar Dionysius in 1997, H.G. Dr. Yakob Mar Irenaios Metropolitan took over the charge of leading the diocese till March 2009. Now following the kalpana dated 2nd March 2009, H.G. Dr. Yakob Mar Irenaios is transferred to Kochi Diocese and H.G. Dr. Yuhanon Mar Diascoros is the new Metropolitan of the Chennai Diocese.
The diocese have a charitable institution called Snehabhavan, a guidance centre for the patients who undergoing the treatment in Christian Medical College, Vellore and Mercy Home, a home for physically challenged children in Eluru, Andhra Pradesh. Diocese has one degree college in Narasimharajapuram, South Kanara, and two colleges - St. Mary’s college, Brahmavar, St. Thomas College, Koyambedu, Chennai running under control of respective parishes. The mercy home in Eluru and college in South Kanara would now be coming under Bangalore diocese. The diocese also runs 2 guesthouses in Chennai city for the youngsters who came to study as well as work in Chennai