Our primary purpose was to provide maximum heart rate (HR(max) ) values for ambulatory children with cerebral palsy (CP). The secondary purpose was to determine the effects of age, sex, ambulatory ability, height, and weight on HR(max) . In 362 ambulatory children and adolescents with CP (213 males and 149 females; age range 6-19y; 195 spastic unilateral, 162 spastic bilateral, and five ataxic CP), HR(max) was measured during a 10-m (Gross Motor Function Classification System [GMFCS] levels I and II) or 7.5 m (GMFCS level III) shuttle run test. The mean HR(max) was 194 (SD 9.9) beats per minute (bpm), with a 95% prediction interval between 174 and 214 bpm. No associations were found in HR(max) related to age, sex, ambulatory ability, height, and weight. Since the HR(max) did not vary with age, equations such as 220-age are not appropriate. When direct evaluation of HR(max) with exercise testing is not feasible, we suggest the mean value of 194 bpm be considered as an estimate of HR(max) at the individual level.