Recent developments in the treatment of Cushing's disease, particularly the trans-sphenoidal microadenomectomy, have prompted a survey of the pathophysiological theories of ACTH hypersecretion in this condition. The results of the trans-sphenoidal approach are reported and the post-surgical evolution (success failure or recurrence) are discussed. It is emphasized that a long fellow up is essential to assess the efficacy of this therapeutic approach.