Because of its secluded character the prison world is the object of distorted perceptions and a vivid imagery, which applies as well and probably, even to a very high degree to both gender and religion. Based on empirical data collected in two Swiss prisons, this article concentrates on two main topics: firstly, the authors describe the ways in which religiosity is expressed and practiced in prison by male and female inmates. Secondly, they comment on the social functions that inmates attribute to religion in prison. If men and women understand and practice religion in a similar manner, on the contrary, it appears that they attribute differentiated function to religion. After sketching out their methodological approach and briefly present their data, the authors connect their findings to the idea that if the institution determines to a large extent the differences in religiosity, the institution itself is organized according to a gendered logic and thereby also promotes a gendered relation to religion.