San Thome Basilica is a Roman Catholic (Latin Rite) minor basilica in Santhome, in the city of Chennai (Madras), India. It was built in the 16th century by Portuguese explorers, and rebuilt again with the status of a cathedral by the British in 1893. The British version still stands today. It was designed in Neo-Gothic style, favoured by British architects in the late 19th century.Christian tradition holds that St. Thomas arrived in Kerala from Palestine in 52 A.D. preached between 52 A.D. and 72 A.D., when he was martyred on St. Thomas Mount. The basilica is built over the site where he was believed originally to be interred. San Thome Basilica is the principal church of the Madras-Mylapore Catholic Archdiocese. In 1956, Pope Pius XII raised the church to the status of a Minor Basilica, and on February 11, 2006, it was declared a national shrine by the Catholic Bishops' Conference of India. The San Thome Basilica is a pilgrimage centre for Christians in India. The church also has an attached museum.

Relics of St.Thomas The National Shrine of St.Thomas Basilica is built over the tomb of Apostle St.Thomas. St.Thomas one of the twelve Apostles of Jesus Christ came to India in A.D.52, martyred in A.D.72 and was buried here in Mylapore. There are only three basilicas built over the tomb of an apostle. St.Peter's at Rome and St.Jame's at Spain (Compestella, Santiago) are the other two. There is an underground tomb chapel below the Basilica. His Holiness Pope John Paul II visited and prayed at this tomb on 5th February 1986. St.Thomas who brought christianity to india is considered to be the Father of Indian Christianity.