The Hawaii Vietnam Veterans Project (HVVP) was congressionally mandated as a follow-up to the National Vietnam Veterans Readjustment Study (NVVRS) to assess current and lifetime prevalence of posttraumatic stress disorder (PTSD). The Hawaii Vietnam Veterans Project used the original two-stage NVVRS design in which a lay interview, conducted with a large sample, was followed by a clinical interview with a smaller subsample. Reported results are from the clinical subsample consisting of 100 Native Hawaiian and 102 American of Japanese ancestry veterans compared with white veterans from the NVVRS cohort. The major finding is that veterans of Japanese ancestry exhibited significantly lower prevalence of current full, current partial, and lifetime full PTSD than white veterans. Adjustment for age and war zone exposure did not eliminate most of these differences. These results indicate that minority status per se is not a risk factor for PTSD.