Cushing's syndrome during pregnancy is a rare and difficult to diagnose disorder. We describe the case of a 30-yr-old woman presenting with symptoms and signs of mild hypercortisolism, in which ACTH-independent Cushing's syndrome was diagnosed. Urinary cortisol excretion was elevated and circadian rhythm of cortisol was absent. ACTH levels were low. In addition, plasma cortisol failed to suppress after a high dexamethasone dose. An abdominal computed tomography scan confirmed a left adrenal mass. While diagnosis work-up was still in progress, the patient became pregnant and wanted to carry her pregnancy to full-term. Hypercortisolism was successfully controlled with metyrapone, which was started at 8 weeks of gestation. At 16 weeks of gestation, a laparoscopic left adrenalectomy was performed. Pathologic examination of the gland showed a benign adrenocortical adenoma. The patient developed secondary adrenal insufficiency and was discharged on 20 mg hydrocortisone daily dose. At 30 weeks of gestation, the patient had a pre-term rupture of membranes and underwent spontaneous vaginal delivery. The newborn was a normal virilized male who weighed 1280 g. No apparent metyrapone-induced teratogenic effects were observed and there was no clinical or biochemical suppression of adrenocortical function. In conclusion, in adrenal Cushing's syndrome during pregnancy, medical treatment with metyrapone as soon as the diagnosis is made, in combination with laparoscopic surgery during the second trimester, are useful in preventing complications secondary to hypercortisolism and safe both for the mother and infant.