Children with cerebral paisy have been reported to have poor growth and delayed skeletal maturation, but it is unclear whether these effects are related to the underlying brain injury or to concomitant mainutrition. This study was designed to evaluate the effects of hemiplegic cerebral palsy on skeletal maturation and growth, with the unaffected side used as each subject's control. Bilateral hand-wrist radiographs were obtained for 19 children with spastic hemiplegia. Skeletal maturation was determined in a blinded fashion with the Fels method. The skeletal age of the affected (hemiplegic) side was less than that of the unaffected (control) side in all 19 subjects; the mean difference in skeletal age was 7.3 months (p<0.001). The delay in skeletal maturation of the affected side correlated linearly with age and upper extremity function. These findings show that brain injury results in delayed skeletal maturation independent of mainutrition. This effect on skeletal maturation may explain, in part, the reason that some children with cerebral palsy grow poorly. © 1994 Mosby-Year Book, Inc.