Children with Attention Deficit Disorder (ADD) often exhibit problems in visual spatial perception, math achievement, and social skills, and it has been postulated that this constellation of behaviors may constitute Right Hemisphere Deficit Syndrome (RHDS). This study examined 21 children with attention deficit disorder with hyperactivity (ADD/H), 11 children with attention deficit disorder without hyperactivity (ADD/WO) and 10 children with dyslexia (LD) to determine if they could be differentiated on the basis of problem solving tasks that tap RHDS functions. Children's ages were between 6 and 16 years. Compared to LD children, ADD/H children scored significantly higher on the externalizing factor of the Child Behavior Checklist and the Math subtest of the Wide Range Achievement Test-Revised. On a judgment of line orientation test, ADD/H children exhibited significantly more right-sided errors whereas ADD/WO children demonstrated left-sided errors. Results provide limited support that ADD/H children exhibit problems similar to children diagnosed as Right Hemisphere Deficit Syndrome. Results also support the notion that ADD/WO children perform more similarly to LD children than to ADD/H children. (16 references) (JDD)