1. In a series of 590 cerebral palsy patients, twenty-five (4.24 per cent) showed evidence of dislocation or subluxation of the hip. Twenty-three of these had spastic cerebral plasy.
2. The dynamic imbalance of the hip in these patients is shown by muscle study. The pathomechanics of coxa valga and of hip dislocation in cerebral palsy are discussed.
3. The treatment of our patients and the end results are presented, stressing the importance of prophylactic tenotomy of the spastic hip adductors and of strengthening the motor power of the cerebral-zero hip abductors by automatic reflex.
4. Dislocation of the hip in cerebral palsy is preventable. If we are aware of the probabilities and understand the pathomechanics, we will regard every child with spastic lower limbs as having potential subluxation or dislocation of the hip.