Descriptive and comparative follow-up studies of young adult males with Asperger syndrome (AS) diagnosed in childhood, using both interview, self- and parent assessment instruments for the study of aspects of emotional well-being, social functioning, and cognitive-practical skills have not been performed in the past. One-hundred males with AS diagnosed in childhood were approached for the assessment using the Asperger Syndrome Diagnostic Interview (ASDI), (personal and parent interview), the Leiter-R-Questionnaires, the Beck Depression Inventory (BDI), and the Dysexecutive Questionnaire (DEX). About 75% of the targeted group participated. The ASDI results came out significantly different at personal vs parent interviews in several key domains. In contrast, the Leiter-R-Questionnaires, showed no significant differences across the individuals with AS and their parents in the scoring of cognitive/social and emotional/adaptive skills. The BDI proved to be an adequate screening instrument for depression in that it correctly identified the vast majority of cases with clinical depression in the AS group. The DEX results suggested an executive function deficit problem profile in males with AS as severe as that reported in groups of individuals with traumatic brain injury and schizophrenia. Interviews (personal and collateral), and self-rating and parent-rating questionnaires all have a role in the comprehensive diagnostic process in AS and other autism spectrum disorders, and could be used as adjuncts when evaluating whether or not individuals meeting diagnostic symptom criteria for the condition have sufficient problems in daily life to warrant a clinical diagnosis of AS. (Contains 5 tables.)