Ovarian malignant melanomas are extremely rare tumors. Most of them are secondary tumors and disseminated metastases are recognized at the time of diagnosis. Primary tumors are even more rare and usually associated with a teratoma. A 67-year-old female had a pelvic mass that was recognized on ultrasonography (USG) and physical examination. Intraoperative pathological consultation was reported as "pigmented solid ovarian tumor, probably compatible with malignant melanoma". Paraffin sections, and histochemical (Masson Fontana and Prussia blue) and immunohistochemical examination (S-100 and HMB-45) were also consistent with "malignant melanoma". This case was accepted as "Probably primary ovarian malignant melanoma" in lack of any other tumor focus on detailed clinical and radiological investigation, skin biopsies or pigmented lesions in medical history. It is reported for being an extremely rare tumor and its distinctive characteristics for differential diagnosis are emphasized.