Growth factors are important molecules mediating both the development as well as adaptive and pathological changes within the cardiovascular system. Growth factors therefore mediate both beneficial and nonbeneficial effects. The beneficial actions include the improvement of endothelial function, stimulation of vascular repair, the formation of new capillaries (angiogenesis), and the growth of collateral arteries (arteriogenesis). These actions represent the conceptual basis for the therapeutic use of growth factors, based on the idea to therapeutically induce or accelerate a given beneficial process. The beneficial effects of growth factors have to be separated from effects where growth factors act as mediators of pathological processes such as atherogenesis and plaque destabilization. This review article focuses on the physiological and beneficial effects of growth factors in the vessel wall and describes and explains the dysfunction of these effects under certain conditions now referred to as "growth factor signal transduction defects".