Based on one and a half year of ethnographic research, this dissertation explores the religious practices of the Baniwa, an Arawak-speaking group of the Brazilian Amazonia whose members have mainly converted to evangelicalism, a Protestant movement, since the mid-20th century. More specifically, I investigate the reorganization of such practices in an urban context, that is among the Baniwa who live in the city and in peri-urban villages. Through a reflection structured around four major themes – Amerindian conversions, growth of evangelical Churches in Brazil, shamanism and indigenous movements – this work sheds light on a little-known aspect of the Amazonian native people’s relation to Christianity. While Amerindian conversions in the Lowlands of South America are generally presented in anthropological literature as an ephemeral or unstable phenomenon, the results of this analysis show the continuity of the Baniwa evangelical movement. Under the influence of indigenous political mobilizations, this movement emancipates itself from the non -native missionaries and pastors and consolidates itself through the constitution of an extensive network of autonomous native Churches, while reconfiguring the place of shamanism in the group.