Knowledge of the impact of childhood psychosocial problems on success in military service is scarce. The purpose of the study was to assess whether childhood psychosocial problems are associated with suitability for military service. The subjects were 2,622 Finnish boys born in 1981. They were first assessed with the Rutter parent and teacher questionnaires and self-reports (Children's Depression Inventory) at age 8. Their suitability for military service was assessed at age 18. A wide range of childhood problems, especially internalizing disorders, predicted release from military service. All informants had predictive association with later suitability for military service. The majority of children with psychiatric problems were later estimated to be fit for military service. The results show a predictive association between childhood psychiatric problems and early adult psychosocial impairment, as estimated by the ability to serve in the military forces.