The role of adrenalectomy in Cushing's syndrome. Forty-four patients with Cushing's syndrome were treated by adrenalectomy between 1975 and 1989. Twenty patients had adrenal adenomas: 13 with obvious Cushing's syndrome and 7 whose disease was subclinical, detected after evaluation of an incidentally discovered adrenal mass (es). Twelve patients underwent bilateral adrenalectomies for Cushing's disease after failed transsphenoidal explorations and pituitary irradiation. Six patients had primary adrenal hyperplasia, five as manifestations of Carney's complex. Two others underwent bilateral adrenalectomies for ectopic adrenocorticotropic hormone from carcinoid tumors. Four patients had adrenocortical carcinoma treated with transabdominal adrenalectomy. Three are alive from 8 years to 5 months. There was one postoperative death (2.3%) caused by coagulopathy and multiple organ failure and three (7%) minor postoperative complications. Follow-up showed good to excellent results in 95% of patients. It is concluded that adrenalectomy provides prompt relief from the severe morbidity of Cushing's syndrome regardless of the cause. It is the treatment of choice for adrenal adenomas, carcinomas, primary hyperplasia, and selected patients with Cushing's disease. 