Pulmonary hypertension (PH) is a condition of increased blood pressure in the pulmonary arteries and is diagnosedwith an increased a mean pulmonary artery pressure ≥25 mm Hg. This condition may be associated with multipleclinical situations. Based on pathophysiological mechanisms, clinical presentation, hemodynamic profiles, andtreatment strategies, the patients were classified into five clinical groups. Although there have been major advances inthe management of PH, it is still associated with significant morbidity and mortality. The diagnosis and treatment of PHhave been performed mainly by following European guidelines, even in Korea because the country lacks localized PHguidelines. European treatment guidelines do not reflect the actual status of Korea. Therefore, the European diagnosisand treatment of PH have not been tailored well to suit the needs of Korean patients with PH. To address this issue, wedeveloped this guideline to facilitate the diagnosis and treatment of PH appropriately in Korea, a country where theconsensus for the diagnosis and treatment of PH remains insufficient. This is the first edition of the guidelines for thediagnosis and treatment of PH in Korea, and it is primarily based on the ‘2015 ESC/ERS Guidelines for the diagnosis andtreatment of pulmonary hypertension.’ with the acceptance and adaptation of recent publications of PH.