OBJECTIVES: Hyperuricemia (HU) and tumour lysis syndrome (TLS) are important complications leading to morbidity and mortality in patients with haematologic malignancies. The objective was to assess the cost-effectiveness (CE), in terms of cost per life year saved (LYS), of preventing or treating HU and TLS with recombinant urate oxidase, rasburicase (FASTURTEC®). METHODS: The current incidence and costs of HU and TLS were studied in a multi-country chart review including 788 adults and children treated for acute lymphoid or myeloid leukaemia (ALL or AML) or non-Hodgkin lymphoma (NHL). Costs, expressed in Euro, were calculated from the UK payer’s perspective. The average life expectancy at the time of diagnosis was based on cancer survival rates and age at diagnosis reported in the literature. Adult data were derived from the Eurocare study, childhood data from UK national statistics. RESULTS: HU incidence was 18.9% and its average cost was 1,679Euro (SE=519). TLS incidence was 5% and its average cost was 11,202Euro (SE2,147), and TLS-related mortality was 0.8%. With 90% reduction of HU and 100% reduction of TLS cases by rasburicase, the average CE of prevention in adults was 20,652Euro/LYS for ALL, 83,824 Euro/LYS for AML and 31,667 Euro/LYS for NHL. The high CE ratio in AML is explained by its low life expectancy. In children the respective results were only 379 Euro/LYS, 668 Euro/LYS, and 388 Euro/LYS. Sensitivity analyses showed these results to be robust, especially in children. If applied only for treatment of established HU/TLS, rasburicase is associated with savings of 1,089 Euro in adults and 2,358 Euro in children, becoming cost-saving as of a 65% and only 24% reduction of TLS in adults and children respectively. CONCLUSION: In prevention of HU/TLS, highly cost-effective results can be obtained in children, and reasonably cost-effective results in adults with ALL. Both in adults and children, treating HU with rasburicase would be a cost saving intervention.