Several previous studies have shown that Attention Deficit Hyperactivity Disorder (ADHD) is common in children with Restless Legs Syndrome and ADHD is more common in adults with this syndrome. This pilot study examined the prevalence of Restless Legs Syndrome in adults with ADHD, showing six of 30 adult ADHD participants (20%) had Restless Legs Syndrome. This estimate exceeds the prevalence (7.2%) for a previously published control group. These six adults had more severe ADHD symptomatology than those without Restless Legs Syndrome based on the overall Conners' Adult ADHD Rating Scale. Such results suggest that symptoms of Restless Legs Syndrome may occur often in adults with ADHD and might worsen the symptoms of ADHD. Replication with a larger sample size is in order.