Background: Volunteer black adolescent females from neighborhoods characterized by high rates of unemployment, substance abuse, violence, and sexually transmitted disease were studied to determine the frequency of condom use and unprotected vaginal sex with steady, older partners during various time periods over the previous 6 months. Goal: To examine associations between having male sex partners who were typically older (by at least 2 years) and adolescent females' sexually transmitted disease (STD)/HIV-associated sexual risk behaviors. Study Design: In this cross-sectional study, 522 sexually active black adolescent females completed a questionnaire and a structured interview, of which a portion assessed the age difference between the adolescents and their typical sex partners. The adolescents' ages, length of relationship and their use of hormonal contraception were identified as covariates. Adjusted odds ratios (AOR), their 95% confidence intervals, and respective P values were calculated to detect significant associations. Results: Sixty-two percent of the adolescents reported their typical sex partners were at least 2 years older. These adolescents were more likely to report never using condoms during the most recent sexual encounter (AOR = 2.0), during the last five sexual encounters (AOR = 2.0), and during the past month (AOR = 2.2). Similarly, having older partners was associated with greater odds of reporting any unprotected vaginal sex in the past 30 days (AOR = 1.7) or the past 6 months (AOR = 1.5). Conclusion: Our findings suggest that many adolescent females have sex partners who are at least 2 years older and that their relationship dynamics do not favor the adoption and maintenance of behavior protective against STD or HIV infection. Prevention programs could include training designed to help adolescent females overcome barriers to safer sex with older male partners.