Three hundred eleven patients with post-cesarean endometritis were treated with clindamycin and gentamicin. Isolation of enterococci in the endometrium was associated with use of cephalosporin prophylaxis (P less than .001). Other risk factors for enterococcus-associated endometritis included increased numbers of vaginal examinations (P = .018) and increased length of internal monitoring (P = .006). Patients with enterococcus-associated endometritis were less likely to respond to therapy with clindamycin and gentamicin than were patients without enterococci (82.4 versus 92.7%, respectively; P = .015). Patients with enterococcus-associated endometritis also were significantly more likely to have wound infection (15.7 versus 3.2%, respectively; P = .001). In a retrospective survey of 14 patients with postpartum enterococcal bacteremias, four (29%) had a poor response to initial therapy.