Cohort CP is a multicentre cohort study, initiated by the Hospices Civils de Lyon in September 2009. Population targeted are children with bilateral cerebral palsy, level GMFCS IV or V, aged from 2 to 10 years at inclusion. They are followed-up during 10 years, at the rhythm of 1 visit per year. At each visit are collected clinical, orthopaedic, radiological and environmental data. The primary objective is to establish the incidence of orthopaedic complications (scoliosis and hip joint) depending on patients' age. Secondary objectives are to describe the sequences over time of these complications and the related pain, to explore the impact of nutrition, surgery, asymmetric postures and environmental factors, and to describe the medical and rehabilitative follow-up of these patients. 385 patients are expected by the end of 2020. We expect of this long-term follow-up to gain tools that permit to improve patient's care and patient's quality of life, by putting in place preventing actions and adapted treatments related to their own pathologies.