173 strains of Staphylococcus epidermidis, isolated from pathological material in Canada, Czechoslovakia, Denmark and Germany, were tested for susceptibility to lysostaphin and major antimicrobial agents. Resistance to antimicrobials was low, except for sulfonamides, some tetracyclines, chloramphenicol and streptomycin. Dissociated type of resistance was observed with tetracycline antibiotics. More than one fourth of strains were resistant to lysostaphin. Therefore, lysostaphin susceptibility is not a differentiating criterion for distinguishing the genera Staphylococcus and Micrococcus