This was a prospective, single-blind, comparative study in patients with diagnosis of puerperal endometritis, carried out at the Loayza Hospital in Lima, Peru. The objective of this study was to evaluate the efficacy and safety of clindamycin and gentamicin in the management of endometritis vs. penicillin, chloramphenicol and gentamicin for 10 days. Sixty-five patients were enrolled and 62 were evaluable for efficacy. Both treatment groups were comparable in the pre-treatment period in terms of age, history of pregnancies, controls by gynecologist, days of disease and fever, clinical symptoms like fever, pelvic pain, pulse, uterine size and in laboratory, in hematocrit and leukocytes count. In the culture of endometrium tissue, 27/32 patients (84.4%) in Group A (penicillin + CAF + gentamicin) and 27/30 patients (90%) in Group B (clindamycin + gentamicin) had positive cultures at baseline; 18 and 22 patients showed anaerobes; 8 and 4 patients showed anaerobes plus aerobes and, one patient in each treatment group showed aerobes only. Peptoestreptococcus and Bacteroides fragilis were the most frequently isolated pathogens. Improvement in locchia fetidity was more rapid in Group B, it turned transparent and not fetid since day 3. Complete cure was significantly better in Group B 24/30 (80%) in comparison with Group A 16/32 (50%) (p=0.02). Partial response was found in 15 patients (43.3%) in Group A and 5 patients (16.6%) in Group B. Only one case was considered as bacteriological failure in Group A and only one patient in Group B was considered as failure and required an additional operation due to residual abscess. Twenty four medical events associated to the treatment were detected in all 65 patients enrolled; the presence of anemia at day 3 and 7 was significantly worse in Group A in comparison with Group B (p<0.001 and p=0.01). Medical events (15 in Group A and 9 in Group B) were mild and transitory and did not need to stop any treatment. In conclusion, both treatment schedules proved to be useful for the treatment of puerperal endometritis in association to the standard procedure of curettage. Complete cure and rapid elimination of locchia was significantly better with clindamycin + gentamicin.