The outcome in childhood leukaemia has shown steady improvement over the last decade and efforts are now concentrated on the stratification of patients by risk factors which may avoid overtreatment of good risk patients and limit dose escalation strategies, including those with bone marrow transplantation, to the higher risk patients. In ALL, risk stratification is based on the presenting white cell count, sex, age and cytogenetics of the tumour cells. Even in acute myeloid leukaemia, the outcome with chemotherapy alone is now sufficient to limit elective allogeneic bone marrow transplantation to those who do not have cytogenetically favourable disease. In non-Hodgkins lymphoma, a dramatic improvement in overall survival from 50% to in excess of 80% has been achieved by an escalation in dose and dose intensity of chemotherapy. With this improvement, the prognostic influence of clinical staging has become less clear and recent efforts have concentrated on determining which groups of patients would be cured by less intensive treatment. As for ALL, there is concern about the potential late sequelae in these highly curable children. There remain groups of unusual tumour types, such as anaplastic large cell and peripheral T cell lymphoma, where there remains much to be learned about the pathogenesis and clinical behaviour. The optimum treatment strategy for these subgroups remains to be clarified.