It was established by Pope Francis on 10 October 2017, and Mar Sebastian Pozholiparampil was appointed its first bishop.

Priests from the Eparchy of Irinjalakkuda volunteered their time to travel to Chennai to provide members who were present in the cities for work and studies.

Neelankarai Gorimedu - Pondicherry Jaya Nagar - Pondicherry St. Thomas Mount Pozhichallur Velacherry Valasaravakkam Poonamallee Athipet Ambatur Kovilpathagai Pattabiram Vellore Kodambakkam Mylapore Hosur Thiruvottiyur Eranavoor Otteri Saint Antony's Syro-Malabar Catholic Church in Noothenchery is the cathedral of The Diocese of Hosur.

[4] The Eparchy of Hosur encompasses the northern region of Tamil Nadu, hosting approximately 50,000 Syro-Malabar faithful in Chennai and an additional 15,000 in nearby cities such as Chengalpattu Dharmapuri, Vellore, and Pondicherry.

Furthermore, the region benefits from the dedicated service of 73 women religious, who administer eight schools and engage in various charitable endeavours.