The subject of this study is the Christchurch Apostolic Church, which is a Pentecostal church with approximately 300 members. Material from the fields of sociology of religion and collective behaviour is referred to, and a brief history of Pentecostalism is included. The church is seen as part of a social movement, Pentecostalism, and comments are made on the organization and functioning of social movements and motivations for participation. The research design included participant observation, a questionnaire, and interviews. The church was found to have grown rapidly during the 1970's and to have a preponderance of youthful members, most of whom had transferred form other churches. Church activities were marked by warmth, enthusiasm, informality, and a strong emphasis on individual participation. Ideology is found to be an important factor in determining the church's development, and this is a characteristic of the Pentecostal movement. Suggestions for further research are made.