From January 1977 to June 1980, coagulase-negative staphylococci caused bacteremia in 22 (17%) of 130 patients receiving immunosuppressive therapy and were the most common cause of all bacteremias. Sixteen (73%) of the 22 patients had granulocytopenia, and eight were isolated in a laminar air-flow room. A Broviac or Hickman central intravenous (IV) catheter was present in 20 (91%) of 22 patients, and soft-tissue inflammation at the catheter exit site was a significant risk factor for bacteremia. Except for debilitating fevers and local mucocutaneous infections, there were no distinguishing clinical features in patients with bacteremia. Most infections responded to cefazolin sodium or vancomycin hydrochloride therapy; catheter removal was necessary in only seven patients. These data show that coagulase-negative staphylococci can be important pathogens in patients receiving immunosuppressive therapy, even when the patients are isolated in a laminar air-flow room, if normal mucocutaneous, host-defence barriers are interrupted by IV catheter-insertion or chemotherapy.