A rare case of ACTH-independent Cushing's syndrome due to carcinoma is described. A thirty-year-old woman presented with systolic-diastolic hypertension, unsuccessfully treated for several months with ACE and beta-blockers. During this period physical changes such as centripetal obesity, rubeosis, and hair loss were observed. Elevated urinary and plasmatic cortisol levels were essential for the diagnosis. Alterations of the circadian rhythm with higher levels in the evening compared to the morning were registered. ACTH was found to be suppressed in several tests. Ultrasound and abdominal CT scan showed a mass involving the left adrenal gland. While waiting for surgery, the patient underwent ketoconazole therapy. The operation was carried out by bilateral chest laparotomy and consisted in a left adrenalectomy with regional lymphadenectomy. At 18 months from the operation the patient is in excellent health, the classic signs of Cushing's syndrome have disappeared and laboratory tests are normal.