Pancreatic β-cells sense and adjust the blood glucose level by secretion of insulin. In Type 1 diabetes mellitus, these insulin-producing cells are destroyed, leaving the patients incapable of regulating blood glucose homeostasis. At the time of diagnosis, most patients still have 20-30% of their original β-cell mass remaining. These residual β-cells are targets for intervention therapies aimed at preventing further autoimmune destruction, in addition to increasing the number of existing β-cells. Such a therapeutic option is highly desirable since it may lead to a full recovery of newly diagnosed patients, with no need for further treatment with immunosuppressant drugs or exogenous insulin administration. In this article, we propose that endothelial progenitor cells, a cell type known to promote and support neovascularization following endothelial injury, may be used as part of a combinational stem cell therapy aimed to improve the vascularization, survival and proliferation of β-cells.