The aim of this presentation is evaluation of the renin-angiotensin-aldosterone system (RAA) in selected diseases of endocrine glands. In patients with acromegaly, Conn's syndrome, hyperparathyroidism, hyperthyroidism, hypothyroidism, phaeochromocytoma and Cushing's disease is possible to formulate the temporarily conclusions according to subsidiary meaning of angiotensin converting enzyme inhibitors (ACE I) in these endocrinopathies. Whereas the ACE I play an important role in the treatment of nephropathy and hypertension in diabetes mellitus.