Cephaloridine has been shown to possess certain favorable pharmacologic features while retaining the desirable antimicrobial properties of the parent compound, cephalothin. The major advantage of cephaloridine is its relatively greater resistance to metabolic degradation, presumably by the liver. This results in more prolonged blood levels in healthy subjects and a longer half-life in patients with severe renal disease. These features, together with reported enhanced antimicrobial activity and lack of inhibition by serum, suggest that it may replace or substitute for the parent compound, cephalothin, provided further clinical trials indicate that it proves to be an effective agent. Suggestions are given for a modified dosage schedule in uremic patients and during hemodialysis.