Two patients with Cushing's disease underwent spontaneous clinical and biochemical remission following a period of secondary adrenal insufficiency. One of the patients was untreated, while the other had been treated with partial bilateral adrenalectomy before. Both patients underwent remission shortly after the administration of dexamethasone for diagnostic purposes and remained symptom free for 2 and 3 years, respectively, which was followed by relapse of the disease. We conclude that although resolution of Cushing's disease may occur spontaneously, probably by hemorrhagic infarction of corticotroph microadenomas, careful follow-up studies are required since the relapse of the disease occurs later in some patients.