This paper investigated effectiveness and challenges in evangelization in the Small Christian Communities in the Catholic Church. Specifically, the study set to analyse the effectiveness of Small Christian Communities (SCCs) in evangelization and explore the challenges encountered in evangelization in these SCCs. The study was based on both primary and secondary data. The study was conducted in 274 SCCs in the five parishes in the Catholic Church in Vihiga County. The key mission of the church is to evangelize to all. The Catholic Church used SCCs as agents of evangelization, therefore prompted and a need for analysis of how effective they have been and if they are challenges encountered in fulfilling the mission.