Pulmonary hypertension (PH) in newborns and infants can present in its idiopathic form or complicate a long list of other diseases. Most of these conditions are either pulmonary or cardiovascular in origin. In the present review our current knowledge regarding pathophysiology, structural changes, diagnosis, and available treatment options for PH in the age group below 1 year of age is summarized. New treatment options available in adults including endothelin receptor antagonists (ETRA) and phosphodiesterase (PDE) inhibitors are presented and the need for randomized controlled trials in newborns and infants is emphasized. Future candidates for pharmacotherapy of PH in infants include among others vasoactive intestinal polypeptide (VIP), PDE-3 and PDE-4 inhibitors, hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, and adrenomedullin (ADM).