Authors present the case of 15-year-old girl with diagnosed pre T-acute lymphoblastic leukaemia with hyperleukocytosis--at admission 213 x 10(9)/l. At clinical evaluation a major peripheral and abdominal lymphadenopathy, mediastinal mass, hepatosplenomegaly were revealed. After administration of prednisone for two times--11.4 mg/m2/24 h--the features of tumour lysis syndrome rapidly increased. Hyperphosphatemia, hyperkalemia and hyperuricemia resulted in acute renal failure. Renal replacement therapy was introduced with simultaneous application of cytoreduction phase therapy and induction of remission according to New York protocol. Total number of performed hemodialysis sessions was 12. Obtained haematological remission in 8th week of treatment is still present. Renal function remains normal. Remission supportive treatment has been continued according to above-mentioned protocol.