Carcinoembryonic antigen (CEA) was elevated (greater than 2.5 ng/ml) in 81 of 100 patients with gynecologic malignancy and in 17 of 95 patients with benign gynecologic disease. CEA concentration was, in general, related to the extent of disease, and in early stage cancer often returned to normal following complete surgical excision. Tumors were classified morphologically according to cell type, lymphoplasmacytic infiltration, necrosis, vascular invasion, desmoplasia, and degree of differentiation. The only histologic characteristic associated with elevated CEA levels was the presence of vascular invasion. Further investigation is needed to define the structure, function, and metabolism of CEA in patients with gynecologic malignancy.