A retrospective cohort study of 97 patients identified by prospective hospital-wide surveillance was conducted to determine the length of hospital stay and mortality attributed to hospital-acquired enterococcal bacteremia. The mean duration of hospitalization for cases was 83 days compared with 44 days for matched controls (p = 0.0001). The mortality rate during the study period was 43% among cases and 12% in matched controls (p less than 0.001). Thus the mortality rate attributable to enterococcal bacteremia was 31% and the risk ratio was 4.75. Stepwise discriminant function analysis indicated that the use of vascular catheters and renal dialysis and the presence of immune deficiency were predictors of fatal outcome in cases. Enterococcal bacteremia has become a prominent nosocomial pathogen and is associated with mortality rates well above those expected from the underlying disease.