Pulmonary arterial hypertension (PAH) is most often diagnosed in its advanced stages because of the non-specific nature of early symptoms and signs. Although clinical assessment is essential when initially evaluating patients with suspected PAH, echocardiography is a key screening tool in the diagnostic algorithm. It provides an estimate of pulmonary pressure at rest and during exercise and is useful in ruling out secondary causes of pulmonary hypertension. In addition, echocardiography is valuable in assessing prognosis and treatment options, monitoring the efficacy of specific therapeutic interventions, and detecting the preclinical stages of disease. Pericardial effusion, indexed right atrial area, the degree of septal shift towards the left ventricle in diastole, tricuspid annular plane systolic excursion (TAPSE), pulmonary vascular capacitance (PVCAP) and RV Doppler index (Tei index or RV myocardial performance index) should be considered prognostic predictors. Non conventional ultrasound techniques, namely tissue Doppler imaging, strain imaging and real time three-dimensional echocardiography, may provide new insights in delineating RV structure and function.