Purpose. Our previous studies showed that transplanted islets increasingly express a marker of neovascularization, platelet endothelial cell adhesion molecule-1 (PECAM-1), as well as vascular endothelial growth factor (VEGF). Hepatocyte growth factor (HGF) is another stimulator of neovascularization. In this study, we examined the expression of these growth factors and their receptors; fetal liver kinase-1 (Flk-1) for VEGF and c-Met for HGF, to acertain whether VEGF and HGF play a role in the neovascularization of transplanted islets.