Pulmonary Arterial Hypertension (PAH) is defined by a persistent elevation in pulmonary artery pressure with normal left-sided pressures. It is characterized by increased pulmonary vascular resistance due to increased vascular tone and structural remodeling of pulmonary vessels. PAH is a quite rare condition, thus considering the rarity, subtle presentation, and diagnostic dilemma commonly posed by this disease, underdiagnosis and underreporting are probably widespread. In order to reach a diagnosis the use of echocardiography, right-heart catheterization and the six-minute walk test is essential. As far as therapy is concerned, the patient should be supported by oxygen, diuretics, anticoagulants, digoxin and suggest life-style changes. After diagnosing the condition ca-blockers should be administered to those who respond positively in acute vasodilation test. Other agents used, target the endothelin pathway (ET-1 blockers such as bosentan), the NO pathway (sildenafil, inhaled NO, L-arginine) and the prostacyclin pathway (prostacyclin analogues). In some cases surgical treatment is essential (atrial septestomy, pulmonary endarterectomy, lung and heart transplantation). Finally, future therapies include administration of VIP and SSRIs. The goals of evaluating pulmonary hypertension are detection, definition of severity and the nature of the hemodynamic lesion and its consequences, diagnosis of causal or associated conditions, and determination of optimal therapy.