Information was gathered in telephone interviews of a national probability household sample of 4,023 youths ages 12-17 years. The youths were interviewed after a parent or guardian and then the participant consented. Variables included age, gender, race, household income, being a victim of sexual assault, being a victim of physical assault, having witnessed violence, meeting diagnostic criteria for posttraumatic stress disorder, alcohol or drug use in the lifetime or over the past year, heavy alcohol use, and the commission of an index delinquency offense. The sample's demographic characteristics were representative of the youth population as a whole. A total of 8.1 percent had experienced sexual assault, 17.4 percent had experienced physical assault, 40 percent had witnessed violence, about 9 percent had experienced a family-discipline assault, and 12.3 percent had committed an index delinquent offense. Almost one in five was involved in problematic alcohol or drug use. Gender differences were as expected regarding experiences of sexual and physical assault. Findings indicated substantial proportions of those who had experienced physical or sexual assault or had witnessed violence were currently experiencing posttraumatic stress disorder. Findings also indicated that drug use and personal victimization are related to juvenile delinquency. Further data analysis will clarify the sequence of these events. The research was funded by the National Institute of Justice. Figures, tables, questions from the audience, answers from the speakers, and introduction by National Institute of Justice Director Jeremy Travis