This report describes a 55-year-old woman who had 1 previous episode of major depression that responded favorably to treatment with tricyclic antidepressants. After the development of Addison disease, she experienced a new episode of major depression that failed to respond to adequate treatment with imipramine and was subsequently successfully treated with electroconvulsive therapy (ECT) with steroid cover. The patient did not experience adrenal crisis or adverse effects. After 9 ECT sessions, she attained full remission. These findings support the suggestion that ECT treatment is safe in patients with Addison disease when using 100 mg intravenous hydrocortisone as prophylaxis.