Ovarian carcinosarcoma is an extremely rare tumor with an incidence of <2%. A report of such a rare case in a 40-year-old multiparous woman is being presented here. The patient complained of abdominal pain and distension. Abdominal computed tomography revealed a variegated mass in the right adnexal region. The CA-125 level was 1635 U/ml. The patient underwent laparotomy and the tumor was removed. Microscopic examination of the tumor showed presence of both carcinomatous and sarcomatous elements. Immunohistochemical analysis revealed that the carcinomatous component was positive for cytokeratin and estrogen receptor and negative for progesterone receptor. The sarcomatous component was positive for vimentin. Ki-67 was positive in 60% cells. A final diagnosis of ovarian carcinosarcoma was rendered. This case is significant owing to extreme rarity of the tumor. Records of similar cases must be maintained for future reference with regard to impact of treatment protocol followed on prognosis.