Several recent papers have shown that both familial primary pulmonary hypertension (FPPH) and sporadic primary pulmonary hypertension (PPH) may have a common etiology that is associated with the inheritance and/or spontaneous development of germline mutations in the bone morphogenetic protein receptor (BMPR) type II gene. Because BMPR-II is a ubiquitously expressed receptor for a family of secreted growth factors known as the bone morphogenetic proteins (BMPs), these findings suggest that BMPs play an important role in the maintenance of normal pulmonary vascular physiology. In the present commentary we discuss the implications of these findings in the context of BMP receptor biology, and relate these data to the genetics and pulmonary pathophysiology of patients with PPH.