Consistent with previous studies, individuals in the study sample were found to experience trauma and victimization, both in and out of their homes, at extraordinarily high rates. The majority of homeless youth of both genders experienced at least one traumatic event and/or clinically significant levels of childhood victimization. Using multiple measures, alarming patterns were found of multiple victimization experiences. These findings indicate that the prevalence of trauma among homeless youth is significantly higher than in other populations of young people, where 20 to 40 percent of youth are exposed to trauma before reaching adulthood. Also, significant gender differences were found in patterns of trauma and victimization experienced by homeless youth. Both male and female homeless youth experienced traumatic events at high rates. Homeless females also exhibited more symptoms of Posttraumatic Stress Disorder (PTSD) than did males, consistent with what has been found in the general population. Experiences of trauma during childhood and adolescence can have grave negative effects on mental health and development. Compared to other adolescents, homeless youth experience trauma and victimization at especially high rates. Although most individuals successfully recover from trauma, a substantial minority will develop PTSD in response to such events. Eighty-five youth recruited from a drop-in center in New York City, the Streetwork Project of Safe Horizon participated in the study. Figures, tables, and references