Hematologic malignancies (leukemia, lymphoma, multiple myeloma, et al.), as well as solid tumours (renal, liver, lung, ovarian, etc.), can lead to acute or chronic renal failure. The most common clinical manifestation is acute renal failure within the tumour lysis syndrome (TLS). It is characterized by specific laboratory and clinical criteria in order to prove that kidney disorders result from cytolysis of tumour cells after chemotherapy regimen given, although on significantly fewer occasions it is likely to occur spontaneously or after radiotherapy. Essentially, failure is the disorder of functionally conserved kidney or of kidney with varying degrees of renal insufficiency, which render the kidney impaired and unable to effectively eliminate the end products of massive cytolysis and to correct the resulting disorders: hyperuricemia, hyperkalemia, hypocalcaemia, hyperphosphatemia, and others. The risk of TLS depends on tumour size, proliferative potential of malignant cells, renal function and the presence of accompanying diseases and disorders. Hydration providing adequate diuresis and administration of urinary suppressants (allopurinol, febuxostat) significantly reduce the risk of developing TLS. If prevention of renal impairment isn?t possible, the treatment should be supplemented with hemodynamic monitoring and pharmacological support, with the possible application of recombinant urate-oxidase enzyme (rasburicase). Depending on the severity of azotemia and hydroelectrolytic disorders, application of some of the methods of renal replacement therapy may be considered.