Windswept hip deformity describes an abduction and external rotation position of one hip with the opposite hip in adduction and internal rotation. Windswept hip deformity may occur in association with hip dislocation and scoliosis. We analysed the prevalence of this deformity in a total population of children with cerebral palsy, and the impact of hip prevention and early treatment of contractures on the prevalence and severity of windswept hip deformity. The frequency of windswept hip deformity was 12% in the control group and 7% in the study group, comprising children in the hip prevention programme. The children with this deformity in the study group had a lower frequency of scoliosis and none had hip dislocation. It thus seems that the hip prevention programme results in a decrease in the number of children with windswept hip deformity, and a decrease in the severity of the deformity.