Abstract Medical missions are criticized for having a secularizing effect. Progressive Pentecostals who combine prayer and Western medicine represent one possible solution to this problem. This article explores whether Western medicine and Pentecostal-charismatic healing practices can be sustainably integrated by offering a case study of the medical missiology of Osvald Orlien. The article shows that Orlien’s model provides a theological conception of holistic health, a fusion of Pentecostalism and the African worldview, and the formation of a Pentecostal theology of medical science that affirms natural laws and human reason. Orlien offered a holistic theology of healing and an account of moral virtues that could be intelligibly defended. He encountered opposition from both Pentecostals who rejected Western medicine and rationalistic skeptics who refused Pentecostal healing practices. The case study also identifies key factors contributing to sustainable, institutional integration of medicine and charismatic practices in the Congolese context.