Clinicians rely primarily on subjective behavioral questionnaires in assessing attention-deficit hyperactivity disorder (ADHD). The new mini-motion logger actigraph, which is a wrist-worn minicomputer, can add an objective element to this assessment and is especially useful in children due to its small size. We applied this technology as an outcome measure in evaluating drug therapy in two children with ADHD who were receiving methylphenidate and pemoline, respectively. We also assessed preliminary findings from an additional 13 children.