The Diocese of Chingleput is made out of the entire civil district of Kancheepuram in the State of Tamilnadu. The diocese of Chingleput was declared an independent new diocese by His Holiness late John Paul II on the 19th July 2002. Most. Rev. Dr. A. Neethinathan, was appointed as the first Bishop of Chingleput. Originally Chingleput diocese was making the southern stretch of the Archdiocese of Madras – Mylapore.
The preliminary preparations for the carving out of the new diocesan territory was initiated since 1987 by Most Rev. Dr. G. Casimir Gnanathikam SJ, the then Archbishop of the Archdiocese of Madras – Mylapore. The bifurcation became a reality during the tenure of Most Rev. Dr. Arul Das James, the Archbishop of Madras – Mylapore in succession.
The diocese of Chingleput comprises of the entire civil district of Kancheepuram in the state of Tamilnadu. As its boundary, the diocese of Chingleput has bay of Bengal in the east, Kancheepuram, the temple city in the west, Chennai, the metropolitan city in the north and Pondicherry, the Union Territory in the south. It has the historically renowned hill shrine of St. Thomas where the Apostle was martyred, and the shrine of the miraculous Mother Mary - Mazhai Malai Madha, Acharapakkam.
Initially the new diocese comprised of 64 parishes with 51 diocesan priests; 30 religious priests and 67 religious congregations. At present the diocese of Chingleput has grown and developed into 84 parishes and two independent shrines 1. St. Thomas National Shrine, 2. Mazhai Malai Madha Shrine with 101 diocesan priests, 50 religious priests and 72 religious congregations.