The National Women's Study, a 2-year, three-wave longitudinal investigation, employed a national probability sample of 3,006 adult women to: (a) identify separate risk factors for rape and physical assault, and (b) identify separate risk factors associated with post-rape posttraumatic stress disorder (PTSD) and post-physical assault PTSD. This investigation differed from previous studies in that it prospectively examined risk factors at the multivariate, as opposed to univariate level. Overall, past victimization, young age, and a diagnosis of active PTSD increased women's risk of being raped. By contrast, past victimization, minority ethnic status, active depression, and drug use were associated with increased risk of being physically assaulted. Risk factors for PTSD following rape included a history of depression, alcohol abuse, or experienced injury during the rape. However, risk factors for PTSD following physical assault included only a history of depression and lower education.