OBJECTIVE The aim of the paper is to investigate the prevalence of posttraumatic stress disorder (PTSD), depression and anxiety in a community sample of New Zealand Vietnam War veterans. METHOD Data were collected as part of a national survey on the health and mental health of New Zealand Vietnam veterans. Five hundred and seventy-three randomly selected male Vietnam veterans participated in a postal survey. The questionnaire contained a number of demographic, biographical and psychological measures. RESULTS The results revealed that 10% of the veterans could be classified as PTSD cases and that these veterans exhibited high levels of depression and anxiety. In PTSD cases, 15% were also classified with anxiety, 6% with depression, and 73% were classified with both anxiety and depression. In PTSD cases 94% were classified with more than one additional disorder. In non-PTSD cases 27% were classified with anxiety, and 1% with depression, while 12% experienced both anxiety and depression. CONCLUSIONS The consequences of comorbidity for research and treatment are discussed and it is suggested that health professionals should be attentive to military experience as a predictor of these disorders.