Churches which have sprung up from immigration are, in many respects, an important object of study for theology. At a time when mainstream Protestant churches are receding, these communities are growing. This success cannot simply be traced to a Pentecostal or Evangelical dimension, since they are affiliated with different confessions or denominations. How then can we explain their power of attraction, as what they offer is rather classical, even traditional, with regard to doctrine and ethics? The diversity within these communities is increasing as new generations no longer always follow cultural identities but, instead, shape international, and even non-denominational, communities. This article addresses such questions and offers a typology of these churches, on the basis of fieldwork in Geneva and the surrounding region. In the conclusion, the author raises a list of questions which deserve to be considered from a reformatory or Protestant theological and ecclesiological standpoint.