Uterus leiomyomas are the most common benign tumors and usually are asymptomatic. This article is a report of an approximately large Myoma (12 × 12 × 21 cm). The subject was a 40-year-old woman with pelvic fracture. While examining, a large mass was found in the pelvic. The patient was transferred to the operation room to further examination. During the surgery an almost constant but stiff mass was found in hypogastrium that overextended to the umbilicus. For the last few months, the patient had some disorders such as constipation and oligomenorrhea but these disorders were not important and discomfortable complaining for the patient. Patient was clinically assumed to have ovarian tumor and referred for laparotomy. After surgery, pathological examination showed that it was a subserosal Myoma.