Background:-Nephrotoxicity is dose limiting side effect of platinum coordination complexes( cisplatin, carboplatin and oxaliplatin) which have revolutionised the treatment of many human cancers. Objective:-To determine the renal and electrolyte abnormalities associated with platinum based chemotherapy. Methods:-70 newly diagnosed cancer patients who were put on combination chemotherapy were evaluated for various renal and electrolyte abnormalities during chemotherapy and were subsequently followed at six monthly intervals for a period of 18 months to ascertain any progression or reversibility in their renal functions. Results :-Among the 70 patients studied, 42 patients received a cisplatin based chemotherapy; 7 received carboplatin based chemotherapy and 21 received oxaliplatin based chemotherapy. Cisplatin was the most nephrotoxic among the three drugs and nephrotoxicity was cumulative. There was successive rise in serum creatinine from 0.68±0.15mg/dl to 1.14±0.53mg/dl and successive fall in creatine clearance from 98.9±15.6ml/min to 67.1±27.6 ml/min with each cycle of cisplatin. I6.7% patients developed azotemia(creat> 1.5mg/dl)after second cycle and 24.4% after third cycle of cisplatin. Nephrotoxicity was uncommon with carboplatin and oxaliplatin. There was persistence of deranged renal functions at followup even after stopping chemotherapy. Serum magnesium also fell sequentially from pre-treatment value of 0.9±0.2mg/dl to 0.61±0.17 mg/dl at sixth cycle. Hypomagnesia persisted in 23 of 35 patients at follow up. Hypokalemia occurred more frequently than hypocalcemia in cisplatin group. Electrolyte abnormalities were less common with carboplatin and oxaliplatin. Conclusions:-Cisplatin has cumulative nephrotoxicity which can persist even after the drug is stopped. Renal functions and electrolytes are to be closely and regularly monitored in patients on chemotherapy even when the drug has been stopped.