All human ovarian tumors (n = 32) analysed were positive for cytokeratin except for a single case. OV-TL 3 stained 96% (26/27) and 1 out of 4 controls, while OC-125 stained 86% (24/27) and 3 out of 4 non-ovarian carcinomas. Androgen receptors predominated (AR-96%) compared to estrogen (ER-32%) or progestin (PgR-50%) receptors in the ovarian carcinomas. Aromatase activity was detected in 6 ovarian carcinomas and in 3 non-ovarian carcinomas. No definite relationship was observed between the parameters measured. Ovarian carcinomas stained brightly with OV-TL 3 and OC-125 had high AR levels, while focal or absent reaction was related to low AR levels. A role for androgens in ovarian cancer is suggested.