Over the past 20 years, numerous studies have been conducted in several countries to investigate leukemia mortality or incidence near nuclear sites. To date, no study examining multiple sites simultaneously has found an increased incidence of childhood leukemia near nuclear facilities. In France, two studies examined leukemia mortality before the age of 25 around half of the sites currently in operation without showing an excess incidence. An excess incidence of leukemias diagnosed before the age of 25 has been suggested around the La Hague site, but the most recent studies have not confirmed an excess around this site. The work presented here constitutes the first systematic study of childhood leukemia incidence around all French nuclear facilities in metropolitan France. This study is presented in greater detail elsewhere. (Introduction)