The case is presented of a 68-year-old male with extensively metastasizing carcinoma of the prostate, in whom severe hypokaliemic alkalosis developed. The urinary excretion of aldosterone and of glucocorticoids was greatly increased and at autopsy bilateral adrenal hyperplasia was found. Despite the elevated glucocorticoid excretion, the only clinical findings suggesting Cushing's syndrome were hyperglycemia and glycosuria. Limited metabolic studies revealed renal wasting of potassium, the constant excretion of an acid urine, and the continued ability to concentrate the urine. Review of the literature suggests that there is a causal relationship in the coexistence of adrenal hyperplasia and cancer of other organs, but it cannot be stated which disease process is primary. In the present case, the prostatic carcinoma seems definitely to have developed first. The possible role of estrogen therapy and castration in the development of adrenal hypcrplasia in this case should be. considered.