Unique features of the pulmonary circulation impact its function in health and disease, not the least of which is the existence of developmentally distinct, functionally heterogeneous extra-alveolar and septal capillary networks. The impact of ion channel expression and regulation in lung vascular smooth muscle or endothelium in these vascular compartments provides a focus for this special topics issue. Reviews and original contributions from experts in the field discuss two broad groups of ion channels, drawing on studies utilizing biophysical and molecular approaches in heterologous expression systems, in vitro approaches in pulmonary vascular smooth muscle and endothelial cells, and physiologic studies in animal models of chronic pulmonary hypertension. First, channels involved in membrane depolarization and related alterations in vascular tone, and shear sensing or exocytosis by endothelium are discussed: voltage-gated potassium channels, ATP-regulated potassium channels and L- and T- type voltage-gated calcium channels. The second series of reviews discusses the role of calcium influx pathways provided by transient receptor potential channels in regulation of pulmonary vascular tone or vascular remodeling, and endothelial barrier function. Understanding the role of ion channels in pulmonary vascular pathophysiology may be critical to development of new therapeutic strategies.