Patients with occlusive atherosclerotic vascular diseases have frequently developed collateral blood vessels that bypass areas of arterial obstructions. The growth of these collateral arteries has been termed "arteriogenesis" which describes the process of a small arteriole's transformation into a much larger conductance artery. In recent years, intensive investigations using various animal models have been performed to unravel the molecular mechanisms of arteriogenesis. The increasing evidence suggests that arteriogenesis seems to be triggered mainly by fluid shear stress, which is induced by the altered blood flow conditions after an arterial occlusion. Arteriogenesis involves endothelial cell activation, basal membrane degradation, leukocyte invasion, proliferation of vascular cells, neointima formation (in most species studied), changes of the extracellular matrix and cytokine participation. This paper is an in-depth review of the research critical to recent advances in the field of arteriogenesis that have provided a better understanding of its mechanisms.