Parental report Child Behavior Checklists (CBCL) of 77 male and female subjects aged 4-18 years were analyzed in this study. Individuals had been given diagnoses of autistic disorder using the Autism Diagnostic-Interview-Revised (ADI-R) within a research project on the genetics of autism. A feature of behavior problems independent of sex but influenced by age and IQ level could be identified for the autistic sample with highest relative scores on the scales measuring attention problems, social problems and thought problems and low scores on the scale for somatic complaints.