Pulmonary hypertension (PH) is a clinical condition characterised by elevated pulmonary artery pressure (PAP) and vascular resistances. At the onset of the disease, symptoms are frequently atypical so that PH diagnosis is usually made when the disease is advanced, which often is too late for efficacious treatment. As a consequence the prognosis is poor. Echo-Doppler evaluation allows: (a) an early identification of patients with PH, (b) to establish a patient's prognosis and (c) to evaluate a proper patient's follow-up. In patients with PH echocardiography provides information about right heart dimensions, pulmonary artery pressures, right ventricle systolic and diastolic function and left and right ventricle interdependence. Most importantly Echo-Doppler evaluation has became a major diagnostic tool for PH allowing evaluation of changes with time and with different treatments which are aimed at reducing pulmonary artery pressure and right heart dimensions and at improving right heart function.