Dual allegiance is not a recent mission problem. Since the very beginning when Satan successfully tempted Adam and Eve the devil has perverted the pure truths of God and deceived people so that they dabble in a syncretistic stew by constantly looking for the latest power source and mixing truth and error. In more recent mission history syncretism, dual allegiance, split-level Christianity, and Christo-paganism have become widespread among those who call themselves Christian. What are the causes, and how can the church effectively intervene? Christian leaders have a growing awareness and concern about “the persistence of a two- tier Christianity around the world despite centuries of instruction and condemnation by missionaries and church leaders. Deeply committed Christians faithfully attend church services and pray to God in times of need, but feel compelled during the week to go to a local shaman for healing, a diviner for guidance, and an exorcist for deliverance from spirit oppression” (Hiebert, Shaw, and Tiénou 1999:15). This paper will briefly describe some of the underlying causes of syncretism and dual allegiance, followed by suggestions on how the church can effectively and appropriately respond in biblical ways.