The majority of cancers occur in adults over the age of 65, with about 70% of all cancer deaths in this population. Tumor lysis syndrome (TLS) is a complication of hematological and others malignancies, caused by massive tumor cell lysis due to chemotherapy, immunotherapy, radiotherapy. TLS can determine an alteration of the body's normal homeostatic mechanisms and cause hyperuricemia, hyperkaliemia, hyperphosphatemia, hypocalcaemia and uremia. Aggressive fluid administration has been recommended in all patients presumed to be at risk of this syndrome. Hyperkaliemia has to be correct with hypertonic glucose, resins and dialysis. Initial treatment of hyperphosphatemia includes phosphate binders. The cornerstone of prevention and treatment of hyperuricemia includes both inhibiting the formation of uric acid as well as increasing its renal clearance through urinary alkalinization, allopurinol, rasburicase. Conventional management to prevent acute renal failure consists of intravenous hydration, diuretic therapy and urinary alkalinization. The management of TLS in elderly patients is often complicated by the renal and the heart senescence and by the presence of multiple co morbid conditions, polypharmacy and difficulties with adherence to complex medication and dietary regimens.