Twenty-one cases in which sarcomas metastasized to the ovaries are reported. The patients ranged from 18 to 79 (average 42) years of age; only five of them were over 50 years old. Eleven tumors were primary in the uterus and 10 outside the genital tract. Three uterine tumors were leiomyosarcomas, and eight, endometrial stromal sarcomas. The extragenital primary tumors were leiomyosarcoma of the stomach (1) and small intestine (2), retrovesical leiomyosarcoma (1), fibrosarcoma of the anterior abdominal wall (1), sarcoma of the mesentery of smooth muscle or neural type (1), hemangiosarcoma probably primary in the heart (1), osteosarcoma of the maxilla (1), chondrosarcoma of the rib (1), and Ewing's sarcoma of the pubic bone (1). The ovarian tumors, most of which were large, were discovered at the same time as the primary tumors in 11 cases; in seven cases, the ovarian tumor was discovered 7 months to 9 years after diagnosis of the primary tumor. In three cases, the ovarian tumors were discovered 4, 7, and 10 months before detection of the primary neoplasm. Two of these tumors were endometrial stromal sarcomas, and one, an epithelioid leiomyosarcoma of the stomach. Eleven ovarian metastases were bilateral. On microscopic examination, the greatest difficulty in pathologic interpretation was posed by the metastatic endometrial stromal sarcomas because of their simulation of sex cord-stromal tumors. Features helpful in their distinction from these tumors included the frequent presence of extra-ovarian disease, bilaterality, and a characteristic content of small arteries resembling the spiral arteries of the late secretory endometrium. The other tumor that caused major diagnostic difficulty was the metastatic epithelioid leiomyosarcoma from the stomach, which had a pattern that initially suggested the solid-tubular pattern of a Sertoli cell tumor.