Objective. To determine prevalence, patterns, and correlates of voluntary flunitrazepam use in a sample of sexually active adolescent and young adult women 14 to 26 years of age. Design. Cross-sectional survey. Setting. University-based ambulatory reproductive health clinics. Patients or Other Participants. There were 904 women self-identified as white, African-American, or Mexican-American. Interventions. None. Main Outcome Measure. Lifetime, frequency, patterns, and physical effects of flunitrazepam use. Results. Lifetime use was reported by 5.9% (n = 53) of subjects, with frequency of use ranging from 1 to 40 times. Flunitrazepam was taken most often with alcohol (74%), and 49% took this substance with other illicit drugs. Logistic regression analyses controlling for age and race/ethnicity found that users were significantly more likely than were nonusers to report lifetime use of marijuana (odds ratio [OR] = 3.6) or LSD (OR = 5.2), having a peer or partner who used flunitrazepam (OR = 21.7), pressure to use flunitrazepam when out with friends (OR = 2.7), and a mother who had at least a high school education (OR = 2.6). Finally, 10% of voluntary users reported experiencing subsequent physical or sexual victimization. Conclusions. Voluntary use of flunitrazepam is becoming a health concern to sexually active young women who reside in the southwestern United States. Young women who have used LSD or marijuana in the past or who have a peer or partner who used this drug appear to be at the greatest risk.