Ninety-five cases of mesonephroma of the ovary from the Emil Novak Ovarian Tumor Registry were examined in order to better delineate the clinicopathologic features of this tumor. The majority of patients were in the perimenopausal age group and 51% were nulliparous. Of the 95 patients 68% had tumor confined to the ovary (F.I.G.O. Stage I), in 19% tumor was limited to the pelvis (Stage II), 11.6% had widespread abdominal metastases (Stage III), and only one patient had extra-abdominal extension at the time of initial evaluation (Stage IV). Five-year survival was 43% overall, 63% Stage I, 17% Stage II, and no survivors in Stages III or IV. Salvage in Stage I cases was not affected by histologic grade, stromal proliferation, relative percentage of “clear cells,” or extent of surgery (total hysterectomy with bilateral salpingo-oophorectomy vs unilateral adnexectomy). Endometriosis was demonstrated in only 9.5% of cases and ascites was seen in 8.4%. The authors believe the tumor to be of mesothelial origin and propose that it be called mesonephroid carcinoma of the ovary.