Abstract Staphylococcus epidermidis is generally considered to be a blood culture contaminant. Over a 5-month period, 13 of 108 surgical intensive care unit (SICU) patients (12%) had positive S. epidermidis blood cultures. Sources of infection recognized were total parenteral nutrition (TPN) lines (38.5%), central venous pressure (CVP) lines (23.1%), intravenous (IV) lines (7.7%), and arteriovenous (AV) shunts (7.7%). Sources were not established in three patients (23.1%), but in two of these patients the septicemia was within 48 hours of death. In the remaining 11, all TPN, CVP, and IV lines were removed, and in two with persistant fever (longer than 12 hours), antibiotics were instituted. One of these patients died of uncontrolled S. epidermidis septicemia. In the preceeding 10 months, seven S. spidermidis septicemias were identified (3.7% of 244 Patients in SICU). There were two contaminants. The antibiograms of the organisms in these nine patients varied. In this study there are six patterns of antibiotic resistance in blood cultures of S. epidermidis. In the epidemic group, all were resistant to penicillin, oxacillin, erythromycin, tetracycline, chloromycetin, clindamycin, and streptomycin, and sensitive only to cephalosporins. This outbreak was controlled by a rigid approach to the technical features of patient care, particularly of central and peripheral lines and hand washing. There were no positive blood cultures of the epidemic S. epidermidis in the subsequent 5 months; the incidence continued at 3.8% of 144 SICU patients. The overall 26.9% mortality rate associated with S. epidermidis septicemia and the extensive antibiotic resistance pattern indicate that S. epidermidis is a significant pathogen in surgical patients.