Studies reveal that people under correctional supervision suffer from health problems in proportionally greater numbers than the general population and that their use of health services is extensive. However, very few studies shed light on this phenomenon. The poor health status of inmates is neither the only nor the most important factor in the understanding of health services utilization in custody. Organization of services, health professional practices, and users' perceptions are all important variables in understanding health care consumption. This review of the literature, mostly Canadian studies, aims at documenting some factors that could help us understand the practices of health care utilization behind the walls.