Malignant mixed mesodermal tumors (MMMTs) are highly aggressive and usually diagnosed at advanced stages. MMMT originates from either the ovary or the uterus. Because this disease is relatively rare, an optimal treatment modality has not yet been established. The authors report four cases of ovarian MMMT (one heterologous MMMT and three homologous MMMTs) during 1990-2011. The patients underwent operation immediately after histopathologically confirmation and were treated with platinum-based combination chemotherapy. The extent of operation, the outcomes of radiation therapy, and the proper chemotherapeutic regimen are still controversial. The authors report herein four cases of ovarian MMMTs alone with a brief literature review.