Christianity in the state of Tamil Nadu, India is believed to be almost 2000 years old. Though, since 1800s, it was believed to have been introduced in at Kanyakumari District, Tamil Nadu by St. Thomas, the Apostle, one of the Apostles of Jesus Christ who was claimed to have landed in Malabar Coast (modern day Kerala) in AD 52. In the colonial age a large number of Portuguese, Dutch, British and Italian Christians came to Tamil Nadu. Priests accompanied them not only to minister the colonisers but also to spread the Christian faith among the millions of non-Сhristians in Tamil Nadu. Currently, Christians are a minority community comprising 6% of the total population. Christians are mainly concentrated in the southern districts of Tamil Nadu - Kanyakumari (48.7% of the population, 2001), Thoothukudi (17%, 2001) and Tirunelveli (11%, 2001).
The Roman Catholic Church (Latin Rite), the Church of South India, the Syro-Malabar Catholic Church, the Syro-Malankara Catholic Church, the Malankara Orthodox Syrian Church and other evangelical denominations constitute the Christian population in Tamil Nadu. The Latin Rite of Roman Catholic Church is the oldest and the largest among all. With 15 dioceses including the Roman Catholic Archdiocese of Madras and Mylapore and the Roman Catholic Archdiocese of Madurai, the Latin Rite has a homogeneous presence throughout the state. The second largest church by number of members is the Church of South India with 8 dioceses in Tamil Nadu. They are Coimbatore Diocese, Kanyakumari Diocese, Madras Diocese, Madurai-Ramnad Diocese, Thoothukudi - Nazareth Diocese, Tirunelveli Diocese, Trichy-Tanjore Diocese and the Vellore Diocese. Church of South India Synod, the highest administrative body of the Church of South India, is in Chennai. The vast majority of Christians in Tamil Nadu are either members of the Latin Rite Roman Catholic Church or the Church of South India. The Pentecostal Mission (TPM) is headquartered in Chennai.