The use of psychostimulants to treat attention-deficit/hyperactivity disorder (ADHD) has been controversial for a number of reasons. In an effort to clarify the extent to which the psychostimulant methylphenidate has abuse potential, the existing published evidence has been reviewed and is summarized here, with an emphasis on delineating a number of related but independent issues that are often confused. Methylphenidate produces behavioral effects associated with abuse potential as assessed by traditional assays, but the relevance of this literature to the clinical use of the drug in the treatment of ADHD is ambiguous at best. Existing neuropharmacologic data suggest that methylphenidate has pharmacokinetic properties that reduce its abuse potential as compared with other stimulant drugs of abuse, such as cocaine.