Ectopic ACTH-syndrome is a relatively rare neuroendocrine disease. It is characterized by hypercortisolemia-associated severe complications that justifies need for timely diagnosis and radical therapy. Case report of young patient with ACTH-producing lung tumor is presented. There was 1-year diagnostic search on background of endogenous hypercorticism. Treatment resulted severe postoperative adrenal insufficiency that demonstrates current difficulties in management of these patients.