To assess the role of the adrenal glands in the development of hirsutism, levels of 11 beta-hydroxyandrostenedione (11 beta-OHA), 17 alpha-hydroxyprogesterone (17-OHP), dehydroepiandrosterone sulphate (DHEAS), androstenedione (delta 4A), and free and total testosterone (T) were measured in 63 hirsute females and 30 control patients. Six of the hirsute patients had basal levels of 11 beta-OHA and 17-OHP and responses to adrenocorticotropic hormone that were significantly greater than these values in controls and the other hirsute women. These women were designated as having an adrenal source for their hirsutism. Women with polycystic ovarian syndrome and idiopathic hirsutism had normal values of 11 beta-OHA and 17-OHP. Levels of total and free T, DHEAS and delta 4A were significantly higher than control values in all of the hirsute women. This study demonstrates that 11 beta-OHA can be used as a marker to assess the adrenal contribution to hirsutism.