The pharmacokinetics of ceftezole, a new cephalosporin antibiotic, was studied in 15 patients with normal and impaired renal function after administering the drug in a 2-hour intravenous drip infusion of 2 g, 81% of the infused dose was excreted in the first 6 h urine of the patients with normal renal function. The pharmacokinetic parameters of ceftezole were obtained by analyzing the serum level data of the drug using a one-compartment open model. The mean serum half-life of ceftezole was 0.64 h in patients with normal renal function and was prolonged to 10.7 h in patients with severely impaired renal function (creatinine clearance: 0-2.6 ml/min.). There was a significant linear correlation between the elimination rate of the drug and creatinine clearance.