Is produced at the right atrium and is acting upon four types of receptors. The main effects of ANF are: renal effects, by rapid increasing and prolongation of glomerular filtration; neuroumoral effects--the inhibition of renin-angiotensin system and of the release of aldosterone; effects upon the vascular wall, with vasodilatation; another effect is the regulation of the hydrosalin balance. The therapeutical endpoints of ANF are related to its action in some diseases like: cardiac failure, arterial hypertension, myocardia infarction, paroxysmal arrhythmias; in some of them it is a very fiable predictive marker. ANF represents o neuroumoral mechanism which play an important role in functional regulation of the cardio-vascular system.