In a previous communication it was assessed that multiple drug resistance plays a decisive role in overall antibiotic resistance of staphylococci and that true data of the extent of multiresistance depend decisively on sufficient number of antibiotics toward which strains of a given species is tested. By analysis of more than 60,000 staphylococcal strains during the period of 1 yr, it was found that triple and quadruple resistance is the most prevalent state in staphylococci, not regarding penicillin resistance which is absolutely predominant. Resistances to streptomycin, tetracyclines, erythromycin and kanamycin (STEK type) are most frequent and mutually selective, i.e., strains resistant to any of these drugs (and also to penicillin, i.e., PSTEK type) show resistance also to other antibiotics of this group. Chloramphenicol resistance seems not to be connected with resistance to these substances nor is resistance to newer specific anti-staphylococcal antibiotics, used only recently, such as oxacillin, lincomycin and cephaloridine. Lincomycin seems to select a co-resistance as many lincomycin-resistant strains were resistant also to oxacillin but not vice versa. Increasing resistance of staphylococci to kanamycin and particularly to erythromycin and their frequent occurrence in multiresistance types is a warning feature which might lead to an increase of therapeutic crisis in staphylococcal infections.