Results of posterolateral iliopsoas transfer in a group of eight children with cerebral palsy with total body involvement and a group of five children with myelomeningocele with neurologic level L4-5 were compared. In the cerebral palsy group, the goal was to obtain a symmetric sitting capacity, and in the myelomeningocele patients the purpose was to avoid luxation and contain the hip joint. Results are expressed in clinical (abduction/range of motion, ROM) and radiologic (migration index, MI) terms. A favorable clinical result was obtained and radiological results were considered moderate in six children in the cerebral palsy group. In four children in the myelomeningocele group, a decrease in MI was achieved. The results support the hypothesis that although in properly selected lower motor neuron lesions the effect of the transfer is beneficial, in upper motor neuron lesions it is less predictable and cannot be distinguished from extensive release procedures.