Fifteen S. aureus strains were isolated from 15 patients with staphylococcal bacteremia. Eight of these strains were tolerant for cloxacillin. Cloxacillin-tolerant strains were also tolerant for most cephalosporins tested except for cephapirin. Strains were not tolerant for clindamycin and gentamicin. Penicillin-tolerant staphylococci showed a high degree of synergism between gentamicin and cloxacillin or cephalothin and gentamicin.