Objective: To bridge theory of response inhibition and learning in children with ADHD. Method: Thirty ADHD and 30 non-ADHD children (ages 9-12) were compared under concurrent variable interval (VI-15 sec., VI-30 sec. and VI- 45 sec.) reinforcement schedules that required the child to switch between the three schedules under conditions of experimentally controlled inhibition (change over delay [COD] vs. No COD). Classical matching law was used to evaluate children's success in maximizing reinforcement opportunities. Results: Children with ADHD showed normal matching only when immediate reinforcement for responding was blocked by the presence of a 3-s COD. Without a COD, ADHD children failed to conform to the normal matching law. Non-ADHD children's behavior fit the matching law (i.e., rate of response was proportional to rate of reinforcement) whether a COD was present or absent. Conclusions: Results supported other findings that response inhibition is a key mechanism in responses to reinforcement schedules by children with ADHD and that the absence of contingencies that inhibit impulsive responding might impair complex learning in which the child must choose between many different behavioral options, each with associated reinforcement schedules. (Contains 5 figures and 3 tables.)