A 39-year-old Japanese woman presented with typical clinical symptoms of Cushing's syndrome, including amenorrhea and hirsutism, for 2 years. The results of her initial endocrine evaluation were consistent with ACTH-independent Cushing's syndrome due to bilateral adrenal masses (diameters of 3.1 cm and 2.4 cm on the left and right, respectively). Serum dehydroepiandrosterone levels were 6,901 ng/mL (normal range 230-2,660 ng/mL). Bilateral laparoscopic adrenalectomies were performed (left adrenalectomy first and right adrenalectomy 3 months later). Following the left adrenalectomy, the results of the endocrine evaluations were still consistent with a diagnosis of ACTH-independent Cushing's syndrome. Serum dehydroepiandrosterone sulphate levels, however, were below the normal range (143 ng/mL). Unexpectedly, the patient's menstruation resumed 2.5 months after the left adrenalectomy. Pathological examination of the resected glands showed bilateral adrenocortical adenomas, one on the left with a diameter of 3 cm, and two on the right with diameters of 0.7 cm and 1.3 cm. Immunohistochemical analysis revealed side chain cleavage, 17α-hydroxylase, 3β-hydroxysteroid dehydrogenase, and 21-hydroxylase immunoreactivity in each adenoma. Dehydroepiandrosterone-sulfotransferase immunoreactivity was pronounced in the left adenoma, less pronounced in one of the right adenoma and weak in the other right adenoma. These results were consistent with clinical endocrine findings. Ours is the first case of a patient with bilateral cortisol-secreting adenomas with unilateral oversecretion of dehydroepiandrosterone sulphate. Resumption of menstruation after the correction of the dehydroepiandrosterone-sulphate excess, despite persistent cortisol excess, indicates the importance of adrenal androgens for the regulation of the menstrual cycle.