Incarceration rates in the United States have tripled over the past two decades and have increased even more rapidly among women than men. To identify risk factors that predict incarceration in HIV-positive (HIV+) and high-risk HIV-negative (HIV-) women and to evaluate the association between continuity of medical care and risk of incarceration, this analysis was conducted. This was a prospective cohort study of HIV+ and high-risk HIV- women enrolled between April 1993 and January 1995 at four urban centers: Providence, Rhode Island; New York, New York; Baltimore, Maryland; and Detroit, Michigan. The HIV Epidemiology Research (HER) Study enrolled 871 HIV+ and 439 high-risk HIV- innercity women between the ages of 16 and 55 years. All participants had a history of injection drug use or high-risk sexual behavior. Interviews, including questions on continuity of medical care and incarceration, were administered at baseline and 6 and 12 months after enrollment. Any incarceration in the 1-year period following enrollment was the main outcome measure. Continuity of care was measured as having seen one healthcare provider for at least 2 years, having received medical care from one usual physician or clinic, and having obtained medical care in a primary care setting as opposed to an emergency room or drug treatment center. Twelve percent of women were incarcerated within 1 year postenrollment. Factors associated with incarceration included recent drug use, prior incarceration, lack of college education, engaging in sex for drugs or money, and having multiple unmet basic needs at the time of enrollment in the study. Continuity of care with a single healthcare provider for more than 2 years prior to enrollment in the study was associated with decreased rates of incarceration even after adjusting for possible confounding factors (OR = 0.67, 95% CI = 0.48 - 0.92). HIV serostatus did not correlate with incarceration. History of prior incarceration and recent drug use were associated with increased risk of incarceration. Continuity of medical care by a single healthcare provider was associated with decreased likelihood of incarceration, suggesting that the provider may play an important role in designing interventions to prevent incarceration in this high-risk population.