The author evaluated psychiatric care in three U.S. prison systems. Major problems included limitations imposed by prison architecture, inadequate staff, medication prescription and distribution by unlicensed, untrained personnel, and a punitive rather than therapeutic attitude. Following the standards of care recommended by American Correctional Association would correct most of these problems. Psychiatrists should guard against prescribing unnecessary medications, particularly minor tranquilizers and sedatives, and should be concerned with prison conditions conductive to mental illness, particularly overcrowding, abuses of solitary confinement, and inadequate programs for inmates who are mentally disturbed but not overtly psychotic. The author recommends minimum staffing standards and suggests considering the transfer of mentally ill inmates to appropriate psychiatric hospitals outside the prison system.