Pulmonary arterial hypertension (PAH) is the most characteristic group of pulmonary hypertensive states. Among other conditions, PAH includes the idiopathic type and forms associated with connective tissue diseases (CTDs), particularly with systemic sclerosis, CREST syndrome, and mixed CTD. Pulmonary hypertension (PH) can be detected by transthoracic Doppler echocardiography. This procedure should be performed routinely once a year in patients with CTD with high risk to develop PAH. The diagnosis of PH needs to be confirmed by right heart catheterization. Recently developed drugs that modulate endothelial function have provided encouraging results in the treatment of PAH with improvement in symptoms, exercise tolerance, and survival.