The structure of the artery wall is exquisitely sensitive to the hemodynamic forces imposed on it by blood pressure and blood flow. This sensitivity regulates growth and remodeling of arteries during development, and it regulates long-term adaptive restructuring of mature vessels. Since many vascular pathologies involve alterations in hemodynamic loads, the sensitivity of arterial structure to these changes inevitably affects the progression of vascular diseases. The processes involved in arterial remodeling involve regulation of vascular cell migration and mitosis and apoptosis rates, control of matrix synthesis and degradation, and regulation of matrix reorganization. Some exciting data have been presented concerning how vascular cells sense mechanical forces, including mechanisms based on shear-sensitive ion channels, control of mass transport of agonists to endothelium by shear strain rate, and modulation of tyrosine phosphorylation of proteins at focal adhesion sites; however, the physiological importance of these mechanisms remains to be elucidated.