Plasma estrone (E1), 17 beta-estradiol (E2), delta 4-androstenedione (delta 4-A) and testosterone (T) levels in the peripheral vein were measured in 28 postmenopausal women with endometrial cancer and 19 control subjects without cancer matched to the cancer patients for age and weight. In the cancer patients, the mean +/- SD plasma E1, E2, delta 4-A and T levels were 53.0 +/- 29.0pg/ml, 31.3 +/- 28.9pg/ml, 1.92 +/- 0.96ng/ml and 0.71 +/- 0.24ng/ml, respectively. In the controls, the mean +/- SD plasma E1, E2, delta 4-A and T levels were 51.2 +/- 27.5pg/ml, 22.4 +/- 10.1 pg/ml, 1.70 +/- 0.6ng/ml and 0.84 +/- 0.24ng/ml, respectively. Similar concentrations were found in the control subjects. The correlation of each steroids with the percentage of ideal weight was examined. The percentage of ideal weight showed no correlation with E1, E2, delta 4-A and T in either group. Insulin response during glucose administration in the cancer patients was examined, and showed no correlation with each steroids. It was concluded that there is no differences between E1, E2, delta 4-A and T levels in cancer patients and control subjects matched to the cancer patients for age and weight. No correlation of insulin with ovarian steroid production was seen in the cancer patients.