Background/Aims: Human immunodeficiency virus-associated pulmonary arterial hypertension (HIV-PAH) is a complication ofHIV infection. Due to improvements in HIV survival rates following the introduction of highly active antiretroviral therapy,HIV-PAH has become an important cause of HIV-related morbidity. Thus, the objective of this study was to explore the prevalenceand characteristics of HIV-PAH.Methods: Ninety-two patients were enrolled in the study from March to August 2010. We investigated clinical characteristics andperformed echocardiography. HIV-PAH was defined as having a mean pulmonary arterial pressure (mPAP) ≥ 25 mmHg based onMahan''s equation, without lung disease or heart disease. The HIV-PAH-possible group was defined as having a tricuspidregurgitation velocity (TRV) of 2.9-3.4 m/s and a pulmonary arterial systolic pressure (PASP) of 37-50 mmHg.Results: Fifteen patients (16.3%) met the criteria of HIV-PAH based on mPAP. With respect to TRV, six patients met the criteriaof the HIV-PAH-possible group. Based on the criteria of mPAP, the duration of HIV infection was not different with or withoutHIV-PAH. HIV RNA titers and CD4 T cell counts tended to be higher in HIV-PAH patients (8,607 ± 11 vs. 1,067 ± 64 copies/mL,p = 0.371; 471 ± 148 vs. 499 ± 252 cells/mm3, p = 0.680, respectively). Echocardiographic indices of the right ventricle weresignificantly deteriorated in the HIV-PAH group as compared with the non-HIV-PAH group (TASPE: 20.52 vs. 23.2, p = 0.001;Tei index: 0.42 vs. 0.39, p = 0.037). In a multivariate regression analysis, HIV activity factors (HIV duration, HIV RNA titer, andCD4 cell count) were not associated with echocardiographic indices of PAH (mPAP, PASP, and pulmonary vascular resistance).Conclusions: In this study, the prevalence of HIV-PAH was comparable to that of previous studies.