The role of VEGF during development and in pathology is well known, but its function in normal adult tissues is poorly understood. Adverse effects associated with the use of anti-angiogenic therapies targeting VEGF in human pathologies have begun to reveal potential functions of VEGF in quiescent vasculature. Further clues from expression studies of VEGF and its receptors in the adult, from the disease preeclampsia, and from experimental neutralization studies, have suggested that VEGF is involved in endothelial cell survival and fenestration, as well as in the signaling and maintenance of non-endothelial cells. The various biochemical properties of VEGF, and its interaction with other growth factors, may be an important point in determining whether VEGF functions as a maintenance factor versus an angiogenic factor. A thorough understanding of the function of VEGF in the adult may lead to more efficacious pro- and anti-angiogenic therapies.