Background and Objective: The treatment of pulmonary hypertension associated with infection by human immunodeficiency virus has not been well defined. Treprostinil is a prostacyclin analogue that has recently been shown to be useful for the treatment of pulmonary hypertension, whether primary, secondary to congenital heart disease, or associated with collagen disease, in a 12-week, double-blind study. We report the results of a one-year follow-up of three patients with pulmonary hypertension associated with human immunodeficiency virus infection who are being treated with treprostinil at our center., Patients and Method: After secondary causes of pulmonary hypertension were excluded by a routine work-up, patients started treatment with subcutaneous prostacyclin (treprostinil) with progressive up-titration of the dose. Functional status and effort capacity were assessed every three months and an echocardiographic study was performed every six months., Results: All patients showed improvement in clinical status, as shown by the NYHA functional class and the results of the six-minute walking test (increase of at least 75 meters). All the patients remain alive after one year of follow-up. Echocardiographic systolic pulmonary pressure decreased in two patients. No serious adverse events were observed., Conclusions: Subcutaneous prostacyclin (treprostinil) seems to be an effective and safe therapeutic option for the treatment of pulmonary hypertension associated with human immunodeficiency virus infection.