The Church of South India affirms that the Church is the Servant of God to carry on the mission rooted in Jesus Christ based on the Scriptures. The Church through her mission expresses solidarity with the broken communities for a new hope to face the challenges of life. The Cross continuous to be the sign of hope for the witnessing Church, which strives towards Unity, Peace and Reconciliation as a vibrant Channel of God.

The Church of South India (C.S.I.) affirms that the purpose of the union is to fulfill the priestly prayer of Jesus Christ, the Lord of the Church "That they all may be one, and that the world may believe that You have sent Me". And the Church of South India would become an effective instrument of God's mission so there will be greater peace, closer fellowship and fuller life in the Church and a renewed commitment for the proclamation of the Gospel of Jesus Christ through word and deed.

Being the largest Protestant church in India, the C.S.I. celebrates her life with Indian culture and spirituality and she also raises her voice for the voiceless on matters of justice, peace and integrity of creation. Sharing the love of Jesus Christ with the people of India, around the world, through proclamation of the good news of Jesus; responding to human need through institutional and emergency relief work; through community development projects and skill training programmes for the marginalized and disadvantaged sections of the people and programmes for the integrity of creation.

The C.S.I. is a united and uniting church moving forward with a dynamic vision for The Communion of Churches in India. The Church of South India, the Church of North India and the Mar Thoma Church are already members of this commune of Churches and are venturing into wider ecumenical relations to witness to One Lord Jesus Christ.

When the church was formed, it had fourteen dioceses with a membership of over one million. Over the last fifty years the membership has grown to over 4 million people with 15,000 congregations spread over twenty two dioceses in the four states of south India (six Telugu dioceses in Andhra Pradesh, three Kannada dioceses in Karnataka, four Malayalam dioceses in Kerala, eight Tamil dioceses in Tamil Nadu) and one in Srilanka; firmly believing in unity in diversity of cultures, languages and liturgical traditions.