OBJECTIVE: Previous studies have identified a high prevalence (25%-80%) of trauma among American Indian and non-American Indian adolescents and adults. However, only a fraction of traumatized individuals develop posttraumatic stress disorder (PTSD). This article examines the relationships of gender and trauma characteristics to a diagnosis of PTSD among a community sample of traumatized American Indian adolescents and young adults. METHOD: Complete data were collected from 349 American Indians aged 15 to 24 years who participated in a cross-sectional community-based study from July 1997 to December 1999 and reported experiencing at least 1 traumatic event. Traumatic events and PTSD were assessed using a version of the Composite International Diagnostic Interview. Logistic regression determined the relationships of gender, trauma type, age at first trauma, and number of traumas to the development of PTSD. RESULTS: Forty-two participants (12.0% of those who experienced a traumatic event) met criteria for lifetime PTSD. While all 4 of the independent variables noted above demonstrated univariate associations with PTSD, multivariate logistic regression analyses indicated that only experiencing a sexual trauma (odds ratio [OR] = 4.45, 95% confidence interval [CI] = 1.76 to 11.28) and having experienced 6 or more traumas (OR = 2.53, 95% CI = 1.06 to 6.04) were independent predictors of meeting criteria for PTSD. CONCLUSION: American Indian children and adolescents who experience sexual trauma and multiple traumatic experiences may be at particularly high risk for developing PTSD.