Pulmonary hypertertension (PHT) is a rare disease defined by increased resistance of the pulmonary arteries inevitably leading to right heart failure if specific treatment is not given. This disease can occur sporadically (idiopathic or primary PHT), within a familial context (familial PHT, BMPR2 gene mutation), or occur as a complication of other diseases (connective tissue disease, congenital cardiomyopathy, human immunodeficiency virus infection, portal hypertension, use of anorexigenic agents). The incidence of primary PHT is 2 million cases per year, probably an underestimation due to the low specificity of clinical signs, predominantly exercise-induced dyspnea. Recent therapeutic advances (prostacyclin and endothelin receptor antagonists administered in continuous infusion) have improved the prognosis of this orphan disease. Inhaled iloprost and type 5 phosphodiesterase inhibitors should be evaluated for this indication. Lung transplantation is reserved for patients unresponsive to medical treatment.