Rasburicase has been defined as a potent urolytic agent for management of malignancy-associated hyperuricemia. We reviewed the data of 26 children with malignancy at risk for TLS who received rasburicase for treatment or prophylaxis of acute hyperuricemia, producing a significant decrease in uric acid level in all the patients. Tolerance of treatment was excellent. Rasburicase is a safe, highly and rapidly effective agent in the treatment and prevention of malignancies-associated acute hyperuricemia.