It is now recognized that, in addition to being able to change its tone acutely, the blood vessel is capable of altering its structure chronically in response to specific conditions. This is mediated by vascular remodeling, an active process that results in a change in the geometry of the blood vessel. It is usually an adaptive process in response to chronic changes in hemodynamic conditions and/or humoral factors. Subsequently, however, vascular remodeling may contribute to the pathophysiology of vascular diseases and circulatory disorders. The purposes of this overview article and of the manuscripts in this journal supplement are to review the pathobiology and consequences of vascular remodeling and to provide a framework for future research in this emerging and important field of cardiovascular investigation.