A new cephamycin antibiotic, cefotetan, was administered intramuscularly to 45 patients with female genital infections including 2 cases with abscess of Bartholin's gland, 14 cases with endometritis, 23 cases with adnexitis and 6 cases with pelvic peritonitis. The daily doses of the drug were 1 to 3 g, with 2 g daily being the most frequent regimen. The treatment was given twice daily in most patients. All cases responded to the drug, and marked response was seen in 22 cases and moderate response in 23. The eradication rate for causative organisms was 64.3%. In 16 cases of S. faecalis, it was rather low at 37.5%. Neither side effects nor abnormalities in clinical laboratory findings attributable to the drug were seen.