The purpose of this study was to assess fitness and gross motor performance of children with ADHD, including users and nonusers of methylphenidate medication. Seventy boys took part in the study. Fitness level of children with ADHD using medication or not, including body composition, flexibility, and muscular endurance, was similar to that of a control group. The only difference was observed for body mass index, which was lower in children with ADHD using medication. Aerobic capacity was also similar when measured by a treadmill test. A lower performance was observed when aerobic capacity was estimated using a field shuttle test, however, suggesting that the methodology used is important. Finally, both groups of children with ADHD presented significantly lower scores for locomotion skills.