This thesis is a study of the history of the Lahu Baptist Church in Thailand during the years 1970-1990. It has been divided into 3 chapters: chapter 1 studies the historical background of Lahu tribes when their ancestors were in China. The descendants are divided into two major groups: the Lahu Na (Black Musshu) and the Lahu Shi (Musshu Luang). The original form of religious faith of the Lahu consists of belief in ghosts, spirits and gods; chapter 2 studies the migrations of the Lahu into Thailand and the Constitution of the Lahu Church, the establishment and the operation of the Lahu Baptist Church in Thailand; and chapter 3 consists of the observation of the Lahu church. It analyzes critically the basis of and motivations for conversion which are prophecy, the former religion, and the conversion of the leader. Various influences that cause problems to arise in the church are: influence from the former religion, prohibitions and taboos of the older people, religious principles, being a tribe that has smaller divisions, and the problem of poverty.