Adult Attention Deficit Hyperactivity Disorder (ADHD) is a life-long, chronic disorder, which has its onset in childhood and is associated with significant functional impairment. ADHD appears to be highly comorbid with other psychiatric disorders, however, literature is lacking concerning ADHD/anxiety comorbidity. To that end, we examined the prevalence of ADHD in an anxiety disorder sample. Consecutive patients referred to an anxiety disorders clinic completed a variety of anxiety disorder self-report measures as well as the Adult ADHD self-report scale and were clinically assessed using the Structured Clinical Interview for DSM-IV, and the ADHD module of the Mini International Neuropsychiatric Interview. Of the 129 patients assessed, the rate of adult ADHD was 27.9%. The mean age of the sample was 33.1 ± 12.5 years, and the mean baseline CGI-S was 4.6 ± 1.1 (moderate to marked severity). The majority of the sample was female (63.6%) and single (49.5%). The most common comorbid disorders associated with ADHD were major depressive disorder (53.8%), social phobia (38.5%), generalized anxiety disorder (23.1%), and impulse control disorders (30.8%). Individuals with ADHD had higher symptom severity scores for obsessive-compulsive disorder, (P= 0.05) and for GAD (P= 0.05) and reported a significantly earlier age of onset for depression as compared to those without (P= 0.05). The prevalence of adult ADHD was higher in our anxiety disorders clinic sample than found in the general population. Clinical implications of these findings are discussed.