Mycoplasma hominis is a commensal organism of the vaginal microbiota; its role as a pathogen is controversial. A 29-year-old female underwent cesarean section complicated by endometritis with pelvic abscess formation. Mycoplasma hominis was cultured in large numbers from intraoperative tissue samples. This case highlights the potential complications linked to M. hominis, a possible pathogen that is commonly missed and not prevented with expanded beta-lactam-based preoperative prophylaxis. Its contribution as a causative organism in the acute infectious process is discussed together with the role of antibiotics.