Ovarian serous tumors of low malignant potential (borderline serous tumors) are intermediate in their clinical behavior between benign serous cystadenoma and malignant neoplasm, and are associated with 10 year survival rates in excess of 90%. Borderline ovarian serous tumors are characterized by absence of stromal invasion but presence of some characteristics of malignancy. Borderline ovarian tumors occur predominantly in premenopausal women, and associated with a very good prognosis. The principal treatment of borderline malignancy is surgical resection of the primary tumor. But approximatley 20% of patients with ovarian tumors of low malignant potential present with Stage III or IV disease at the time of diagnosis. The benefit of postsurgical therapy in this group of patients has not been well established. We report two cases of advanced ovarian serous borderline tumor, one of which was treated with 3 cycles of cisplatin-taxol chemotherpy.