Infections caused by antibiotic-resistant staphylococci continue to be a serious problem and to present a difficult diagnostic and therapeutic challenge. Here we shall not review the voluminous literature that has accumulated on this problem during the last decade. Rather, we shall summarize our experiences with vancomycin* therapy of serious staphylococcal infections. Characteristics of Drug Vancomycin is relatively new and is derived from a new species, Streptomyces orientalis.1,2 It is available as the hydrochloride and is unrelated chemically to any other antibiotic. The molecule is relatively large (weight ±3,300). The drug is bactericidal for staphylococci that are multiplying. It inhibits synthesis of ribonucleic acid in the staphylococcus but causes little or no change in the rate at which protein or desoxyribonucleic acid is synthesized.3 Vancomycin, a predominantly antistaphylococcal agent, inhibits and kills both penicillin G-sensitive and penicillin G-resistant organisms when it is given in small amounts. For several hundred