We used a contingent acoustical feedback procedure to increase appropriate walking and decrease toe walking exhibited by a young boy with autism. After a pre-treatment screening assessment suggested that toe walking was maintained by automatic reinforcement, we paired an auditory stimulus (i.e., a clicking sound) with access to a preferred item to establish the sound as a conditioned reinforcer. Next, we delivered acoustical feedback contingent upon appropriate walking on a continuous schedule. We then thinned the delivery of acoustical feedback to a fixed ratio 8 schedule and eventually discontinued delivery altogether. Finally, we conducted two generalization probes (one pre-treatment and one post-treatment) in another setting. The results suggest that the contingent acoustical feedback procedure was effective to increase appropriate walking and decrease toe walking.