The diagnosis of Cushing's syndrome remains a challenge in clinical endocrinology. Cushing's syndromes are usually classified as dependent or independent from ACTH. In the first class are Cushing's disease, the ectopic corticotropin syndrome and the rare ectopic CRH syndrome. These ACTH-dependent Cushing's syndromes usually present diffusely hyperplastic adrenal glands. In the second class, are cortisol producing unilateral adrenocortical adenomas or carcinomas. New entities have recently emerged as bilateral adrenal hyperplasia not dependent from ACTH; their etiopathogenies are heterogeneous with illicit expressions at the adrenal level of functional receptors to various ligands: GIP, catecholamines, lutropin... The knowledge of such entities has to be taken into consideration in the diagnostic and management of ACTH independent Cushing syndromes.