Primary malignant mixed Müllerian tumor (MMMT) of the ovary is an extremely uncommon neoplasm. These tumors show very aggressive clinical course and high mortality as compared to epithelial ovarian neoplasms. The objective of present study is to present a rare case of primary MMMT homologous type of ovary for its aggressive clinical course and immunohistochemistry findings. A 48-year-old woman presented with complaints of lower abdominal pain, dullness of 3 months duration. USG abdomen pelvis revealed bilateral ovarian solid and cystic mass lesion suggestive of malignant potential. Peritoneal fluid cytology reported as positive for malignant cells. Patient underwent exploratory laparotomy which showed large bilateral ovarian masses with extensive nodular deposits all over pelvic-abdominal organs. Optimal debulking surgery was performed and specimen examined for histopathology. On histopathology, it was reported as bilateral ovarian MMMT homologous type. Immunohistochemistry was done which showed the tumor cell expression positive for CK, EMA, CK7, CA-125, and WT1. Also a distinct population tumor cells express Cyclin D1 and focal and patchy expression of CD-10. Tumor was negative for Desmin, PLAP, Calretin, and inhibin. The patient received operative, chemotherapy and adjuvant therapy along with extensive electrolyte, nutritive, and supplementary support. The patient, however, rapidly deteriorated and died within 9 months of postoperative day. Primary ovarian MMMT is an extremely uncommon neoplasm, and it showed extensive aggressive clinical course and even with operative, chemotherapy, and adjuvant therapy, the patient yields poor prognosis.