&NA;Plasma steroids, estrogen, progesterone, and testosterone, and plasma gonadotropins FSH and LH were determined before and after adrenal suppression in an 18‐year‐old patient with gonadal dysgenesis (XX/XO). Total plasma estrogen was initially low (9.2 ± 2.4 pg/ml) and did not change after adrenal suppression. Plasma progesterone (380 ± 18 pg/ml) and testosterone (236 ± 8.6 pg/ml) were in the range found in the normal follicular phase and fell to 50 ± 17 pg/ml and 112 ± 2.0 pg/ml, respectively, after adrenal suppression. Mean levels of FSH and LH were unchanged after adrenal suppression. These results suggest that the adrenal may make a significant contribution to plasma levels of progesterone and testosterone in patients with gonadal dysgenesis and may also contribute to the plasma levels of these steroids during the follicular phase of the menstrual cycle.