Adrenal adenomas producing both aldosterone and cortisol (A/CPAs) have been described in only a few cases. Correct subtype classification is necessary for making therapeutic decisions in primary aldosteronism (PA). Therefore, we studied in detail the clinical, hormonal and histological features of this entity in two patients with A/CPAs. We describe two patients with A/CPA and present their endocrine evaluations at baseline, after suppression with fludrocortisone and dexamethasone, after therapy with spironolactone and after unilateral adrenalectomy. Moreover, the expression of corticotropin (MC2R) and angiotensin II type 1 (AT1R) receptors and 17alpha-hydroxylase in the tumors of these two patients was analyzed by immunohistochemistry. Aldosterone, 18-hydroxycorticosterone (18-OH-B) and 18-hydroxycortisol (18-OH-F) were not suppressible with fludrocortisone in either patient and were partly suppressible with dexamethasone in one of the patients. Adrenal insufficiency developed in both patients after operation and lasted for more than 6 months. Aldosterone and hybrid corticosteroids returned to normal 8 weeks after adrenalectomy. In both cases, immunostaining showed weak expression of AT1R and MC2R but strong expression of 17alpha-hydroxylase. The most common germline mutations in the aldosterone synthase gene and the aldosterone synthase/11beta-hydroxylase hybrid gene were absent. These two cases document the fact that sporadic A/CPA is a subtype of PA. The presence of an A/CPA should be considered if a patient has both PA and hypercortisolism.