Heart-lung transplantation (HLT) and lung transplantation (LT) remain important therapies for idiopathic pulmonary arterial hypertension (IPAH), but recent advances in medical therapy can substantially delay or even obviate the need for transplantation, especially in certain PAH populations. By the early 1990s, the advent of epoprostenol, initially introduced as a bridge therapy to transplantation, in fact resulted in a survival advantage for IPAH. These benefits were comparable to those of HLT, and many patients who were thought to be destined for HLT were subsequently removed from active listing. Since 2005, however, the impact of the new lung allocation score (LAS) on IPAH has increased waiting list mortality. In the new millennium, the balance between the role of available medical therapies for PAH, the existing issues of the current LAS regarding the PAH patient, and the inherent morbidity associated with transplantation of PAH, will be critical to optimizing patient outcomes. The following discussion mainly focuses on adult IPAH, with some reference to congenital heart disease (CHD) and secondary PAH.