The patterns of mortality among 24,235 US Army and Marine Corps Vietnam veterans were compared with that of 26,685 non-Vietnam veterans using standardized proportional mortality ratios. The veterans were a random sample of deceased Vietnam-era veterans identified in a Veterans Administration computerized benefit file. Military service information was obtained from military personnel records, and cause of death information from death certificates. Statistically significant excess deaths were observed among Army Vietnam veterans for motor vehicle accidents, non-motor vehicle accidents, and accidental poisonings. Similar findings have been reported in other studies of Vietnam veterans. Suicides were not elevated among Vietnam veterans. The Marine Corps Vietnam veterans appeared to have an increased mortality from lung cancer and non-Hodgkin's lymphoma. Although exposure to several environmental factors may be speculated, this study did not investigate possible etiologic factors for these elevated malignancies.