We examined the association of illicit drug use with stress and sexual behaviors among 407 women, aged 18?31, who attended family-planning clinics in southeast Texas between June 2002 and May 2003 (n = 407). Paired comparisons of each of three types of drug users (of ecstasy, marijuana only, and other illicit drugs except ecstasy) with nonusers were assessed by logistic regressions. After controlling for demographics, both ecstasy users and marijuana-only users had a higher score on the stress scale than nonusers. All drug users were at higher risk of more lifetime sexual partners than those who had never used drugs, while those who had used ecstasy were more than twice as likely to have had prior sexually transmitted infections as those who had never used drugs. This study demonstrates that young, low-income women who use ecstasy experience higher levels of stress than nonusers. Stress level is correlated with drug use and participation in risky sexual behaviors. If stress is associated with drug use and risky sexual behavior, interventions designed to reduce substance use and risky sexual behavior in these women may need to also address factors that lead to increased stress. The study's limitations were noted.