It is becoming increasingly recognized that one third to one half of children diagnosed as having attention deficit/hyperactivity disorder (ADHD) continue to exhibit symptoms of the disorder into adulthood. The nature of the clinical picture is not well understood by a substantial number of clinicians. The purpose of this study is to report on the demographic and clinical profile of 56 adults, age 19 to 65 years (48 men, eight women) who present with adult ADHD and meet DSM-III-R criteria for the disorder. Patients underwent a diagnostic work-up consisting of medical and psychiatric evaluation, a structured interview Schedule for Affective Disorders and Schizophrenia-Lifetime Version [SADS-L]), the Symptoms Checklist Revised (SCL-9OR), Conners Attention Deficit Disorder With Hyperactivity (ADDH) scale, structured interview of ADDH, the Global Assessment of Functioning Scale (GAF), and, when available, information from parents was obtained. Ninety-one percent of our sample met the Utah Criteria for adult ADHD. The majority of the sample had additional DSM-III-R diagnoses and only seven had ADHD diagnosis alone. Fifty-three percent of the sample met the criteria for generalized anxiety disorder, 34% alcohol abuse or dependence, 30% drug abuse, 25% dysthymic disorder, and 25% cyclothymic disorder. These findings were similar to those reported in the literature.