The French National Registry of Childhood Haematopoietic Malignancies and the French National Registry of Childhood Solid Tumours jointly ensure the surveillance of cancer in children aged less than 15 years in mainland France. During the period 2000–2004, the registries recorded a total of 8473 cases: 3446 cases of haematological malignancies and 5027 cases of solid tumours. The average number of sources per case was 2.7 and diagnosis was documented by cytology/histology in 94% of cases, ensuring high quality data. The age-standardized incidence rate for all cancers combined was 156.6 cases per million children per year, with a sex ratio of 1.2. The most frequent cancers were leukaemia (29%), central nervous system tumour (23%), lymphoma (12%) and neuroblastoma (8%). In France, an estimated one out of every 440 children presents with cancer before the age of 15 years. The incidence rates are close to those of other industrialized countries, but somewhat higher than those estimated by the French local registries for the period 1990–1999, probably because of improved methodology or perhaps a real increase in some rates. The French National Registries of Childhood Cancer have shown that they are able to fulfil public health surveillance missions satisfactorily and support the national programme for research on childhood cancer.