Adenofibrocarcinoma of the ovary is quite rare. Although 17 cases have been mentioned in the literature, some of which may reflect different entities since clinical and pathologic discussions with followup have been found only in a few isolated instances. We have reported 4 patients who showed atypical and frankly carcinomatous changes involving the glandular epithelium of adenofibromas. In none was there evidence of metastasis or local spread. This neoplasm is frequently asymptomatic, growing quite large before discovery.