Increased pressure in the pulmonary circulation, or pulmonary hypertension, is a common disorder that may complicate various cardiopulmonary conditions, including severe obstructive airways disease and left ventricular dysfunction. An increase in pulmonary arterial pressure that is not due to coexistent cardiopulmonary disease, known as pulmonary arterial hypertension, may occur in the absence of a demonstrable cause (idiopathic or familial); as a complication of systemic conditions, such as connective tissue disease, HIV infection, or chronic liver disease; or as a result of the use of fenfluramine anorexigens, amphetamines, or cocaine. The development of disease-specific therapies for pulmonary arterial hypertension over the past decade underscores the importance of diagnosing pulmonary hypertension early in the course of the condition and implementing a treatment strategy that is based on the condition's cause and severity. In this review, the authors present approaches to the diagnosis and management of pulmonary arterial hypertension, using a hypothetical case to highlight the key management points.