One of the seven original dioceses of 1877, Thumpamon is the largest diocese in the Church, known for its reforms, institutions and monasteries.
Counts above reflect Orthodox-held institutions only; churches, chapels, and other properties currently under schismatic occupation are catalogued separately below and are not included in these totals.
The Diocese of Thumpamon was established in 1877 at the Veliyanad Synod, convened under Patriarch Ignatius Peter IV, which divided the Malankara Church into seven dioceses. Centred on its head church, St. Mary's Orthodox Syrian Cathedral (Thumpamon Valiya Pally), traditionally founded as early as 717 CE, it began with 21 parishes. Konattu Geevarghese Mar Yulios was first Metropolitan, followed by St. Gregorios of Parumala, who governed from 1883 to 1902 and greatly strengthened its spiritual life.
Later Metropolitans, including Geevarghese Mar Philoxenos (Puthencavu Kochu Thirumeni) and Daniel Mar Philoxenos, established regional landmarks such as the Catholicate High School, which became Catholicate College, and built the Bishop's House. Thumpamon has been a trendsetter in the Church, pioneering the structured salary and transfer system for priests and serving as the cradle of the Orthodox Youth Movement and the Student Movement. It has grown from a small cluster of nineteenth-century churches into over a hundred parishes and chapels, and is renowned for humanitarian and monastic institutions including the Basil Monastery, St. Antony Monastery and St. Mary's Convent, which provide free healthcare, scholarships and housing.
As of 2024 the diocese had 13,900 families and is the largest in the Church, overtaking Niranam because of heavy emigration from Niranam's territory, although Thumpamon's numbers are also declining. It is led by its thirteenth Metropolitan, H.G. Abraham Mar Seraphim.
7 districts, listed alphabetically.