Within an interdisciplinary research project, the long-term outcome of children with fetal alcohol syndrome was studied. Methods for the assessment of psychopathology, behavior, and intelligence included psychiatric interviews, behavior checklists for parents and teachers, and intelligence tests. The children were assessed during preschool age, early school age (6 to 12 years), and late school age (> or =13 years). An excess of psychopathology, (including hyperkinetic disorders, emotional disorders, sleep disorders, and abnormal habits and stereotypes) with a strong persistence over time was found. Cognitive functioning was marked by a large proportion of mentally retarded children and also did not change considerably over time. This long-term outcome study reflects the handicapping effects of fetal alcohol syndrome.