In a cohort of 50,465 Swedish men conscripted for military service in 1969-70, the relative risk for suicide was 3.1 (95% Cl 2.3-4.0) among those who had a psychiatric diagnosis at conscription, and 16.7 (95% Cl 13.8-20.1) among those who had a psychiatric diagnosis in in-patient care during a 13-year follow-up. Of the diagnoses at conscription, only neurotic disorder, personality disorder and drug dependence were associated with a significantly increased risk for future suicide. Among those who were admitted to hospital, almost all in-patient diagnoses were associated with a significantly increased suicide risk. Although a psychiatric diagnosis in in-patient care was a strong predictor of suicide, only 44% of all 247 men who committed suicide had ever been treated in in-patient psychiatric care.