Background: The number of HIV infections among adolescents is increasing, and youth in psychiatric care are at particular risk because of their high rates of risky sexual behavior. Methods: As part of a larger longitudinal study examining AIDS-risk behavior among adolescents in psychiatric care, this pilot study investigated the relationship between parent communication about sex and sexual risk-taking among treatment-seeking adolescents. Adolescents reported their risky sexual behavior (e.g., inconsistent condom use, sex with multiple partners), and parents reported how frequently they bring up topics related to sex, HIV/AIDS, and birth control. Parents and adolescents participated together in videotaped discussions of fictional vignettes describing situations related to sex, birth control, and AIDS/HIV. Quality of the parent-teen discussions was coded based on a system developed by Whalen, Henker, Hollingshead, and Burgess (1996) to code AIDS-related discussions. Results: Quality but not frequency of parent-teen communication was associated with adolescent sexual risk-taking, and ethnic differences in communication were found. Conclusions: Findings from this pilot investigation underscore the importance of studying the relationship between parent-teen communication and risky sexual behavior among troubled youth and provide direction for the development of family-based intervention programs that focus on parental behavior during conversations with teens.