A patient with hypoadrenocorticism was found to have low basal plasma concentrations of ACTH and lipotropins and deficient responses of these hormones to insulin-induced hypoglycemia and lysine vasopressin. The adequacy of secretion of other anterior pituitary hormones was assessed either directly, by measuring their concentration in plasma, or indirectly, by assessing end organ function, under basal and stimulated conditions. The responses of gonadotropins to LRH and of PRL and TSH to TRH were normal. The etiology of this rare condition of isolated deficiency of ACTH and lipotropins remains to be elucidated.