More than 5000 cases of malignant renal tumour diagnosed in children under the age of 15 years during the period 1978-1997 in Europe, were extracted from the database of the Automated Childhood Cancer Information System (ACCIS). In 1988-1997 the age-standardised incidence rate of childhood renal tumours in Europe was 8.8 per million, with significant differences between regions. Wilms' tumour (WT, M-8960) accounted for 93% of renal tumours and about 7% were bilateral. The incidence rates of WT increased over the 20 years, by 0.7% per year. European 5-year survival for children diagnosed with WT in 1988-1997 was 85%, ranging from 73% in the East to 91% in the North. Patients in the age group 0-3 years at diagnosis had a more favourable prognosis (5-year survival 87%) than those diagnosed later (81%), P<0.0001. Patients with unilateral WT (n=2085) had better 5-year survival (85%) than 154 patients with bilateral tumours (76%), P=0.003. Five-year survival for 64 patients with clear cell sarcoma of kidney was 68%, for 43 patients with rhabdoid tumour of kidney it was 23%, and for 56 patients with renal cell carcinoma it was 87%. For combined European data, 5-year survival for WT increased from 73% in 1978-1982 to 87% in 1993-1997 and the increase was significant in three out of five regions (East, North and West). Further development and exploitation of the ACCIS database will benefit clinical management and aetiological studies.