Recent epidemiological studies have evaluated the concomitant occurrence of several disorders in children. Over the last few years there have been reports from Anglo-Saxon investigators that many children with attention deficit disorder-hyperactivity also have anxiety disorders. This is the first French study addressing this issue. The prevalence and types of anxiety disorders were determined in 50 children with attention deficit disorder-hyperactivity using a questionnaire and a semi-structured interview. Over 40% of subjects had at least one concomitant anxiety disorder meeting DSM-III-R criteria. Hyperanxiety and separation anxiety were the most common anxiety disorders. Among patients with anxiety, over 40% had more than one anxiety disorder. These data are consistent with earlier Anglo-Saxon reports. Symptoms of anxiety which discriminated hyperactive children with and without anxiety disorders were identified.