Pulmonary arterial hypertension (PAH) associated with chronic lung disease of infancy can be a life-threatening disease affecting an increasing number of former premature infants. There is a need for improved delivery of targeted PAH therapies for this subgroup of patients who have severe and persistent PAH despite standard respiratory care for chronic lung disease. Currently infants who have severe PAH despite oral or inhaled therapy receive continuous intravenous prostanoid therapy (mostly epoprostenol), which is complicated because of the need for central venous access and associated catheter-related complications. We present a series of 5 infants who were successfully treated with a continuous infusion of subcutaneous treprostinil, which is a longer-acting prostanoid with similar hemodynamic effects. There were improvements in echocardiographic assessment of right ventricular function and estimated pulmonary hypertension, and in respiratory support required within weeks of therapy. Unlike commonly in adults, these 5 infants had no instances of severe site erythema, bleeding, bruising, or infection. In our experience with 5 former extremely preterm infants who had PAH associated with chronic lung disease, subcutaneous treprostinil was safe, efficacious, and well tolerated. We believe that subcutaneous treprostinil can be beneficial in a select group of former premature infants who have chronic lung disease and severe pulmonary arterial hypertension who have not responded adequately to conservative therapies.