This chapter begins by exploring the distinct characteristics of the Church of South India (CSI), including its mission heritage and journey from an ecumenical movement to an established mainline institution. After this, an insight into the aspects of church growth and decline in the last three decades will be analysed. The key factors such as: change in human demography, urbanisation and economic development will be carefully observed. But most importantly, the chapter will highlight the impact of Pentecostal and charismatic movements, as well the explosive growth of independent churches upon CSI. Moreover this chapter will outline how these aforementioned aspects have shaped and continue to shape the values and principles of both institutions and their relationship with the wider Anglican Communion.