The mission statement of the CSI is "The Church of South India affirms that the church is the servant of God to carry on the mission rooted in Jesus Christ and 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 continues 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 (CSI) 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 and fuller life in the Church and a renewed commitment for the proclamation of the Gospel of Jesus Christ through word and deed.