The pharmacokinetics of cefmenoxime were determined after a 30-min intravenous infusion of 15 mg/kg of total body weight to 33 adult subjects with normal renal function (CLCR, greater than 80 ml/min per 1.73 m2, group I), mild renal insufficiency (CLCR, 40 to 79 ml/min per 1.73 m2, group II), moderate renal insufficiency (CLCR, 10 to 39 ml/min per 1.73 m2, group III), or severe renal impairment, (CLCR, less than 10 ml/min per 1.73 m2, group IV) or to patients between hemodialysis (CLCR, less than 10 ml/min per 1.73 m2, group V). Concentrations of cefmenoxime in serum and urine were determined by high-pressure liquid chromatography, and serum concentrations were fit to a two-compartment model. There was no significant relationship between creatinine clearance and either peak serum concentrations or volume of distribution at steady state. Patients in group I excreted 81% of the dose into the urine within 24 h; recovery decreased with worsening renal function. The mean terminal half-lives in groups I to V were 1.06, 1.50, 3.55, 4.60, and 11.4 h, respectively. There were good linear relationships between creatinine clearance, and the elimination rate and total body clearance of cefmenoxime. Dosage recommendations for subjects with renal insufficiency are proposed.