The object of this study was to test vascular endothelial growth factor (VEGF) for angiogenic activity in the rabbit corneal assay. VEGF doses ranging from 20 ng to 1000 ng were incorporated into a slow release polymer and implanted into the avascular rabbit cornea. Capillary formation in the cornea was visually analyzed on a daily basis and examined with histology, transmission electron microscopy and scanning electron microscopy of vascular corrosion casts on days 2 and 7 post-implantation. VEGF implants (200ng to 1000ng) consistently stimulated angiogenesis. This neovascularization occurred in the absence of inflammation. We conclude that VEGF acts directly on endothelial cells, initiating and mediating the formation of capillaries.