We studied causes of death in a cohort of all young males (n = 50,465) conscripted for military service in 1969-70. Six hundred eighty three deaths occurred in the cohort during the follow-up through 1983. Injury-related deaths accounted for 75% of all deaths. Of these, 38% were definite suicides, 10% undetermined suicides and 30% motor vehicle accidents. The validity of officially recorded causes of death was studied by scrutinizing all death certificates (n = 683) and forensic reports, including police reports, toxicological and histological data, from a sample (n = 322) of deaths with unclear circumstances. Of 161 officially recorded suicides (E950-959), only one case was reevaluated into poisoning, "undetermined" (E980). Of 47 cases officially recorded "undetermined" (E980-989), 9 were reevaluated into definite suicide (E950-959) although we believe that this is still an underestimation of "true" suicide cases. An alcohol concentration of more than 0.1 g% was found in 45% of all violent deaths (E800-999), 34% of all suicides and 60% of all "undetermined" deaths. We conclude that the causes of death in most cases of injury related death in young age are recorded with high accuracy. Reevaluation of recorded deaths from "undetermined" causes revealed a number of definite suicides, although the "true" number of suicides is difficult to assess even after close scrutiny of the information available.