Endogenous sex hormones seem to influence the risk of several common and debilitating diseases. With a view toward better understanding the effects of surgical removal of the ovaries and high-dose pelvic radiotherapy on plasma sex hormone levels, we measured estrogen and androgen concentrations cross-sectionally among 147 women who had been treated for cervical cancer 0.3-18.5 years previously. Pelvic radiotherapy (mean dose to ovaries, 50 Gy) and bilateral ovariectomy were associated with similarly reduced hormone concentrations relative to levels among nonirradiated women with intact ovaries, most of whom had had early-stage disease and were treated by hysterectomy. There was little evidence that radiotherapy in addition to ovariectomy further lowered concentrations below levels associated with ovariectomy alone, such as might be expected if radiation was suppressing adrenal endocrine function. Among women age 50 years or older at the time of blood drawing, the removal or irradiation of the ovaries was associated with approximately 45% lower concentrations of estradiol (mean ratio [MR], 0.55; 95% confidence interval [CI], 0.32-0.95) and testosterone (MR, 0.57; 95% CI, 0.32-0.99), and 25-30% lower concentrations of estrone (MR, 0.69; 95% CI, 0.44-1.09) and androstenedione (MR, 0.76; 95% CI, 0.47-1.23), relative to the hysterectomy-only group. Among women younger than 50, ovariectomy and radiotherapy, alone or in combination, were associated with 83% lower estradiol concentrations (MR, 0.17; 95% CI, 0.09-0.31), 46% lower estrone concentrations (MR, 0.54; 95% CI, 0.37-0.81), 23% lower androstenedione concentrations (MR, 0.77; 95% CI, 0.57-1.04), and 14% lower testosterone levels (MR, 0.86; 95% CI, 0.64-1.15).(ABSTRACT TRUNCATED AT 250 WORDS)