An expert committee representing multiple disciplines has developed “Diagnosis and Management of Pulmonary Arterial Hypertension: ACCP Evidence-Based Clinical Practice Guidelines.” This committee was impaneled at the request of the American College of Chest Physicians (ACCP) Health and Science Policy Committee, with the endorsement of the ACCP Board of Regents, who had selected pulmonary hypertension as a priority for evidence-based guideline development in 2001. Ten years ago, the ACCP formed a consensus panel on primary pulmonary hypertension (PPH), which provided a well-received and concise general review of the pathobiology, diagnosis, and treatment of PPH. The objective of the current project was to create a guideline broader in scope and more evidence based than the earlier consensus statement. The Duke University Center for Clinical Health Policy Research provided the review and summaries of the current evidence on this subject. The resulting evidence-based recommendations are targeted toward an audience of cardiologists, pulmonologists, rheumatologists, and primary care physicians, as well as other health-care providers who treat pulmonary arterial hypertension (PAH).