Estradiol, progesterone, 17-hydroxyprogesterone, androstenedione and CA125 were assayed in 25 women (12 oophorectomized before entering the study) with ovarian carcinoma. The data from patients were ordered according to the presence or absence of the gonads. The patients with ovaries (Group A) showed significantly higher levels of estradiol (p less than 0.01), progesterone (p less than 0.01) and 17-hydroxyprogesterone (p less than 0.01) than controls. This difference was not observed between oophorectomized patients (Group B) and controls. CA125 levels were significantly higher in patients that in controls (p less than 0.001) irrespective of the ovarian status of the patients. Eleven patients were followed during chemotherapy. Significant reductions of estradiol (p less than 0.01) and CA125 (p less than 0.001) levels after three courses of chemotherapy were observed. These data confirm that women with ovarian carcinoma produce an abnormal amount of steroids. Nevertheless, a marked difference between patients with and without ovaries was observed, suggesting that reported data might be biased by the presence of gonadal tissue. Thus the clinical application of steroids as tumor markers in unselected patients is limited.