The seroprevalence of hepatitis C (HCV) infection was examined among a sample of incoming inmates in the Texas Department of Criminal Justice (TDCJ) prison system. Rates were compared across demographic factors and three types of prison facilities: substance abuse felony punishment units (SAFPs), state jails and prisons. The study sample consisted of 3712 incoming inmates incarcerated for any duration, dating from 1 November 1998 to 31 May 1999. Among males, inmates entering SAFPs and state jails had comparable HCV infection rates (29.7 and 27.0%, respectively) to those entering prisons (27.3%). Among females, inmates entering prisons had a higher rate of infection (48.6%) than those entering state jails (35.1%) or SAFPs (38.3%). For both genders, blacks exhibited a lower overall infection rate than whites and Hispanics, and HCV seroprevalence increased in a stepwise fashion with age. All subgroups of TDCJ inmates, including those held in alternative correctional facilities, exhibited HCV infection rates that were comparable with previous reports of inmate populations, but dramatically higher than general community samples. Given that most inmates held in alternative facilities will return to the general community in a short period of time, understanding the HCV infection rates in these subgroups holds particular public health relevance.