The pharmacokinetics of cephacetrile were studied after its administration as a single i.v. bolus injection of 15 mg/kg body weight to 11 patients with terminal renal inpairment undergoing haemodialysis for 6 h. A two-compartment kinetic model was used to describe the biphasic decrease in plasma concentration. The quantities of antibiotic in the central and peripheral compartments, and the amounts eliminated, were calculated for different times. During haemodialysis sessions, the average pharmacokinetic parameters of cephacetrile determined at the dialyser input were: a = 5.03 h-1, beta = 0.458 h-1, K12 = 2.337 h-1, K21 = 1.996 h-1 K13 = 1.154 h-1, Vc = 5.5081, Vp = 6.4481, Vdss = 11.9561. As a function of the pharmacokinetic parameters of cephacetrile, a regimen of multiple doses was established for patients with terminal renal impairment, which will guarantee safe and effective concentrations of the antibiotic.