Differences between 37 aggressive and 37 nonaggressive children with attention deficit hyperactivity disorder (ADHD) were evaluated as was their response to two doses of methylphenidate (0.3 and 0.5 mg/kg) using a multimethod battery of behavior ratings, laboratory tests, and direct observations. Aggressive ADHD children differed little from nonaggressive ADHD children except that nonaggressives displayed more problems with inattentiveness at school than aggressives while mothers of aggressives reported more symptoms of psychopathology in themselves than mothers of nonaggressives. In their drug responding, aggressives and nonaggressives were quite similar. The few exceptions were on measures of conduct, on which the aggressives were initially rated as more extreme and subsequently showed the greater degree of improvement from medication than nonaggressives. Results replicated those of a previous study and further indicate that aggressive and nonaggressive ADHD children share a common disorder of ADHD but aggressives have more impaired family situations.