Pulmonary hypertension (PH) has been partially reclassified during the 2003 Third World Symposium on Pulmonary Arterial Hypertension held in Venice. PH is a common disorder that may, complicate a variety of cardiopulmonary diseases, including severe COPD, left ventricular failure and chronic thromboembolic obstruction of the pulmonary arteries. Pulmonary arterial hypertension (PAH) is an increase in pulmonary arterial pressure which is not due to classical coexistent cardiopulmonary disease. PAH usually occurs in the absence of an evident cause (idiopathic or familial) or it may be associated with connective tissue disease, HIAI infection, chronic liver disease, congenital systemic-to-pulmonary shunts, venous or capillary involvement, thyroid or myeloproliferative disorders as well as a result of the use of toxic agents and anorexigens. The actuality of developed disease -specific treatments over the past decade, emphasises the importance of an early screening and detection of PH which, even optimally treated in advanced stages, still remains a progressive lethal disease in most of its forms. Early identification represents a real challenge for the clinician: in fact, it is believed that an early recognition and, thus, an early treatment, might be associated with improved survival. In this review, after a short introduction on disease prognosis, we will focus on screening and early recognition of some categories of PH, based on a sequential approach that includes clinical suspicion, detection and differentiation of pulmonary hypertension. This strategy should consent to reach an assessment of severity, ultimately providing the best selective use of therapies.