BACKGROUND The prevalence of ADHD features during childhood and its relationship to the course and presentation of panic in adults with panic disorder was examined. METHODS The presence of DSM-III-R ADHD was retrospectively ascertained in a cohort of 85 adults with panic disorder by structured interview. RESULTS Childhood ADHD features occurred in 23.5% of panic subjects; 9.4% satisfied full DSM-III-R criteria for ADHD, 14.1% had 'subthreshold' diagnoses. Two-thirds of panic patients with ADHD indicated persistence of symptoms into adulthood. Fewer had married or completed college than those with panic alone. There was no significant difference in clinical pattern and severity of panic, or comorbidity of adult Axis I and childhood anxiety disorders in both groups. CONCLUSION Given its frequency and persistence, ADHD comorbidity is an important clinical consideration in all panic patients. Its co-occurrence does not influence the clinical pattern of panic, but may contribute to adverse social outcome.