A register of children born between 1970 and 1979 in the South East Thames Regional Health Authority, and diagnosed as having pre-, peri-, and postnatal cerebral palsy, was set up between 1978 and 1981. We report the 527 children born between 1970 and 1974 for whom ascertainment is virtually complete. The estimated prevalence was 2.2 per 1000, with 7.4% multiple births, and 58% boys. Birthweight distribution is as expected, with 35% weighing less than 2500 g at birth. Parental permission for release of detailed medical information was sought, and the clinicians responsible gave us data on the type of cerebral palsy; details of impairments, disabilities, and anticipated future prospects; and an opinion on the probable timing of the cause. There was a high incidence of orthopaedic defects which must represent a considerable use of resources, although the prevalence of hearing and vision defects suggested that some of these may be undetected.