Objective: Describe the general health, comorbidities and health service use among U.S. children with ADHD. Method: The 2001 National Health Interview Survey (NHIS) contained the Strengths and Difficulties Questionnaire (SDQ; used to determine probable ADHD), data on medical problems, overall health, and health care utilization. Results: Asthma was two and headaches were three times more prevalent, and overall health was significantly lower, among children with SDQ ADHD. Of children with SDQ ADHD, 45% saw a mental health professional in the past year and over half were not taking medication regularly. Urban residence, age (9-13), higher family education, having health insurance, and having comorbid emotional problems were associated with mental health care utilization in children with SDQ AD/HD, while race, gender and family income were not associated. Conclusions: Children with SDQ AD/HD had more medical problems and were more likely to visit the emergency room. Treatment data suggest a problem with under-treatment of ADHD in the United States. Interventions should be targeted in rural areas, and among families with low education and without health insurance. (Contains 3 tables.)