The objective of this study was to present the long-term results of total adrenalectomy for Cushing's disease. Forty-four patients undergoing total adrenalectomy for Cushing's disease between 1953 and 1989 at Leiden University Medical Center, The Netherlands, were studied retrospectively. Remission was achieved in 42 patients (95%), with a mean duration of 19 years. Adrenal remnants were observed in 12 patients (27%), and were without clinical consequence in the majority of patients, but caused early recurrent disease in 2 patients. Nine patients (20%) experienced Addisonian crises up to 30 years following treatment. Nelson's syndrome developed in 10 patients (23%) 7-24 years following total adrenalectomy. Prior pituitary irradiation was a protective factor against Nelson's syndrome as it delayed its onset (p = 0.025). On the other hand, subnormal dose or noncontinuous glucocorticoid replacement therapy was associated with increased risk of development of Nelson's syndrome (p = 0.047). The incidence of Nelson's syndrome increased with prolonged follow-up, and female patients seemed to be at increased risk. Quality-of-life assessment showed less favorable scores on mental health and health perception scales, for which no explanation can be found except the long-lasting metabolic effects of Cushing's disease, even when successfully treated. In conclusion, total adrenalectomy remains the final treatment for Cushing's disease. The presence of adrenal remnants which can cause recurrent disease and the development of Nelson's syndrome during prolonged follow-up enhance the need for continued regular follow-up. Pituitary irradiation prior to total adrenalectomy delays the onset of Nelson's syndrome.