• Staphylococcus epidermidis is emerging as a cause of morbidity and mortality in immunocompromised patients. From January 1980 through June 1982, there were 150 episodes of septicemia in 92 children with leukemia and lymphoma at Memorial Sloan-Kettering Cancer Center, New York. Staphylococcus epidermidis was the fourth most common organism isolated, responsible for 12.7% of all septicemic episodes. Only nine of 53 isolates were sensitive to methicillin; all were sensitive to vancomycin. Staphylococcus epidermidis septicemia was associated with immunosuppressive chemotherapy (94.7%); broad-spectrum antibiotics (79.0%); catheters and drains (73.7%); neutropenia (63.2%); skin or soft-tissue infections (42.1%); prior septicemia (42.1%); concurrent polymicrobial septicemia (21.1%); and prolonged hospitalization (mean, 39 days). Of 19 patients, two died. Increased awareness of the pathogenic potential of S epidermidis in children with hematologic malignancies and prompt alteration of therapy to an effective antimicrobial agent, in most cases vancomycin hydrochloride, is required when the organism is isolated In patients known to be at risk with clinical evidence of septicemia.