Dalit Liberation Sunday is being organised by the National Council of Churches in India (NCCI) and the Catholic Bishops Conference of India (CBCI).
They are asking Christians to show their solidarity with India's 300 million Dalits by praying for them on Sunday.
Although caste discrimination was abolished under the Indian Constitution in 1950, India's Dalits continue to be marginalised in Indian society today.
Dalits face being attacked or physically abused and are often forced to undertake the worst kinds of jobs.
In the summer, there was international outcry when thousands of Dalits were evicted from Delhi to stop visitors to the Commonwealth Games from seeing the city's slums.
The Methodist Church has given its support to the day of prayer. The Rev David Gamble, former President of the Methodist Conference, recently attended the 40th anniversary celebrations of the Church of North India.
He said: "I am very pleased to see that the Indian Churches are addressing the caste question, for example at the recent National Council of Churches Conference on Justice for Dalits.
"Anything that can be done here to support their efforts, by prayer and action, will contribute to the Gospel call to mission in today's world."
Lord Harries of Pentregarth, former Bishop of Oxford and Chair of the All Parliamentary Group on Dalits, said caste discrimination was still a major problem in India, including in its churches.
He said: "I warmly commend Dalit Liberation Sunday and hope very much that churches of all denominations will include the Dalits of India in their prayers on that day."
Bishop Dr V Devasahayam, Bishop of the Madras Diocese of Church of South India, himself a Dalit, addressed the National Ecumenical Conference on Justice for Dalits last month in New Delhi.
He said: "The Indian church is in a sorry state. Church will fail if it does not weed out caste within and outside. Both cannot go together as Christianity is life giving while casteism is a sin and scandal.
"Christ must save us from the abominable sin of caste," he added. "If He can't, then the Gospel is powerless."
Churches are being invited to remember the issue of caste discrimination in their sermons and prayers tomorrow.
A special liturgy for Dalit Liberation Sunday, together with a range of other resources for prayer and reflection, can be found on the NCCI website nccindia.in