One hundred eighteen women who developed endomyometritis after cesarean section in Parkland Memorial Hospital were treated with parenteral cefotaxime sodium. The requirement for additional antimicrobial therapy was significantly higher at an initial daily dose of 3 g/day (16.4%) than when the dose was 6 g/day (4.8%) (P less than .05). The latter clinical efficacy and the observed in vitro susceptibility of 88% of isolates indicate that cefotaxime is well suited for single-agent parenteral therapy for this polymicrobial pelvic infection. Subsequently, 120 women with the same diagnosis were randomly treated with cefotaxime or clindamycin and gentamicin. Patient populations, surgical variables, in vitro microbiologic data, and side effects were similar for both groups. Clinical success observed was also similar: it was 97.5% for women given cefotaxime and 95% for women given clindamycin and gentamicin.