Approximately 1 in 109 adult women was under the care, custody, or control of adult criminal justice authorities on any given day in 1998, the year for which the most recent statistics on women in correctional institutions are available. Of the 84,400 women who were in prison in 1998, a large percentage--37% in state facilities and 72% in federal prisons--were charged with drug-related offenses. Besides drug use, an additional determinant of HIV infection among incarcerated women may be prior exposure to physical and sexual abuse. Linkages among histories of childhood sexual abuse, physical abuse, drug use, and sex work are believed to explain the disproportionately high prevalence of HIV infection among incarcerated women. Historically, HIV services have had to compete with other demands on correctional budgets for funding and personnel time, even though the correctional health care unit is a unique and highly cost-effective access point for providing HIV prevention and care for high-risk populations of women. Coalition building between correctional staff and medical staff (and, in some cases, departments of public health) has enabled some correctional institutions for women to establish outstanding programs for HIV-infected women. By diagnosing HIV and instituting a plan for treatment, correctional facilities for women can play a critically important role in the reduction of morbidity and mortality among HIV-infected women in high-risk populations.