Tubo-ovarian abscess in pregnancy is extremely rare. In this report, we present a patient who had asymptomatic tubo-ovarian abscess during pregnancy. It was diagnosed incidentally immediately after vaginal delivery. Emergency laparotomy was followed and surgical findings included a 4 cm-sized, right, ruptured tubo-ovarian abscess with massive purulent contamination of the whole pelvic cavity. Right salpingo-oophorectomy and massive irrigation were performed.