During physical activity, children with attention deficit hyperactive disorder (ADHD) are often challenged by coordination problems and specific deficits in cognitive function, including information encoding and retrieval. The purpose of this study was to examine aerobic capacity of children with ADHD. The design was repeated measures. Eight hundred ninety two middle school children ages 11-14 including 55 children with ADHD participated. While controlling for age, sex, sports participation, and BMI, children were tested on the Progressive Aerobic Cardiovascular Endurance Run (PACER) three times (September, December, & April). Procedures specified in the FITNESSGRAM test manual were explicitly adhered to. Hierarchical linear modeling (HLM) was applied to analyze the data. As hypothesized, children with ADHD performed 8.6 fewer laps at intercept (baseline), than did healthy children without ADHD (t(878)=-6.207, p<.001). However, no significant differences emerged for time (slope). Also, no significant interactions were found for ADHD with age, sex, sports participation, or BMI. A diagnosis of ADHD, independent of selected predictor variables, explained lower PACER performance. Further studies should examine strategies to help children with ADHD perform optimally on the PACER.