An apparently unique strain of Staphylococcus aureus, resistant to penicillins (including penicillinase-resistant penicillins), cephalosporins, cephamycins, aminoglycosides (all but amikacin), tetracycline, lincomycin, erythromycin, and, in a lesser percentage, to chloramphenicol as well, was isolated on more than 100 occasions over a 20-month period in a general hospital in San Sebastian, Spain. Forty-two (60%) of the 70 patients infected were patients in the newborn nursery. Many of these infants contracted serious disease. In the epidemiologic study of the nursery, this Staphylococcus strain was found in the air and on the clothing of the staff, although no nasal, perineal, or axillary carriers were found among the personnel.