The United States leads the world in creating prisoners, incarcerating one in 100 adults and housing 25% of the world's prisoners. Since the 1976, the US Supreme Court ruling that mandated health care for inmates, doctors have been an integral part of the correctional system. Yet conditions within corrections are not infrequently in direct conflict with optimal patient care, particularly for those suffering from mental illness and addiction. In addition to providing and working to improve clinical care for prisoners, physicians have an opportunity and an obligation to advocate for reform in the system of corrections when it conflicts with patient well-being.