Seven primary ovarian angiosarcomas were diagnosed in 7 patients 20 to 32 (mean 26) years of age. The most common clinical presentation was abdominal pain and distention. Three tumors were in the right ovary and 3 in the left; one was bilateral. Four tumors were Stage I and 3 Stage III. The tumors were brown and hemorrhagic, ranging in maximum dimension from 6 to 13 (average 10) cm. Microscopically, 5 tumors were pure angiosarcomas and 2 were associated with a dermoid cyst. Follow-up information ranging from 2 months to 9 (average 3.6) years was available for 5 patients. Three patients, all with Stage III disease, died of tumor (1 with a pure angiosarcoma, 2 with tumors arising in a dermoid cyst) 2, 15, and 30 months postoperatively. Two patients with Stage I disease and follow-up data were alive and healthy 5.5 and 9 years postoperatively. The differential diagnosis of these tumors is discussed and the literature reviewed.