The tumor lysis syndrome (TLS) is a metabolic disorder resulting from a massive tumor breakdown. It is characterized by hyperuricemia, hyperphosphatemia, hypocalcemia and hyperkalemia and predisposes to acute renal failure. TLS usually occurs after the initiation of cytotoxic therapy and is more frequent in the case of neoplasias with a high proliferative rate or that are highly chemo-sensitive. We report the case of a man with a recurrent kidney cancer who presented with a TLS and acute renal failure after initiation of sunitinib.