Therapeutic angiogenesis constitutes a fundamental survival mechanism that acts to preserve the integrity of tissues subjected to ischemia. Supplemental administration of angiogenic cytokines--as recombinant protein or plasmid DNA--have been shown to augment collateral development when endogenous angiogenesis is suboptimal for organ function, and thus constitute a novel therapeutic option for the treatment of cardiovascular disease. These angiogenic cytokines, all of which share in common the ability to act as mitogens for endothelial cells, do not promote angiogenesis in an indiscriminate fashion; thus angiogenic cytokines selectively produce neovascularization in the ischemic tissues. The purpose of this review is to consider the mechanisms responsible for therapeutic angiogenesis which develops endogenously as well as strategies which have been devised to augment this response. The development of blood vessels is considered from the context of the embryonic paradigm; certain principles which have emerged from studies of pathologic neovascularization; and, principally, the development of collateral blood vessels supplying ischemic tissues, either endogenously or in response to administered growth factors.