Cancer patients aged 15 -24 years have distinct special needs. High quality cancer statistics are required for service planning. Data presented by primary site are inappropriate for this age group. We have developed a morphology-based classification and applied it to national cancer registration data for England 1979 -1997. The study included 25 000 cancers and 134 million person -years at risk. Rates for each diagnostic group by age, sex and time period (1979 -83, 1984 -87, 1988 -92, 1993 -1997) were calculated. Overall rates in 15 -19 and 20 -24-year-olds were 144 and 226 per million person -years respectively. Lymphomas showed the highest rates in both age groups. Rates for leukaemias and bone tumours were lower in 20 -24 year olds. Higher rates for carcinomas, central nervous system tumours, germ-cell tumours, soft tissue sarcomas and melanoma were seen in the older group. Poisson regression showed incidence increased over the study period by an average of 1.5% per annum (P50.0001). Significant increases were seen in non-Hodgkins lymphoma (2.3%), astrocytoma (2.3%), germ-cell tumours (2.3%), melanoma (5.1%) and carcinoma of the thyroid (3.5%) and ovary (3.0%). Cancers common in the elderly are uncommon in adolescents and young adults. The incidence of certain cancers in the latter is increasing. Future studies should be directed towards aetiology.