Following agreement on definitions and classification, a central database was set up to include information on over 6000 children with cerebral palsy (CP) from 13 geographically defined populations in Europe. The overall rate for the period 1980 to 1990 was 2.08/1000 live births (95% CI 2.02 to 2.14). One in five children with CP (20.2%) was found to have a severe intellectual deficit and was unable to walk. Among babies born weighing less than 1500 g, the rate of CP was more than 70 times higher compared with those weighing 2500 g or more at birth. The rate of CP rose during the 1970s, but remained constant during the late 1980s. Future analyses will include data from children born in the 1990s. This collaborative work provides a powerful means of monitoring trends in birthweight-specific rates of CP and an infrastructure for research and service planning.