Primary ovarian leiomyosarcoma is a rare ovarian sarcoma, primarily affect postmenopausal women. It has a nonspecific appearance in the US, CT, and MRI. Here we describe the case of a 71-year-old woman presented with three months of vaginal bleeding, progressive abdominal distention and left pelvi-abdominal mass, with no other complaints. Physical examination, ultrasound, Computed tomography and magnetic resonance imaging revealed a left ovarian tumor with no ascites and no lymphadenopathy. On histology and immunohistochemistry, a diagnosis of leiomyosarcoma was made. Postoperatively the patient did not receive chemotherapy or radiotherapy, and she was doing well after16 months follow-up and disease free on clinical and radiological examination.