Circulating angiogenic cells (CACs), represent a potential new therapeutic tool for the treatment of cardiovascular diseases, but their regenerative function is impaired in patients with coronary artery disease (CAD) and cardiac risk factors. The objective of this study is to assess the effect of lentiviral overexpression of endothelial nitric oxide synthase (eNOS) on the activity of CACs from patients with CAD and cardiac risk factors. In vitro and in vivo assays were employed to evaluate the regenerative capacity of the cells compared to CACs derived from healthy volunteers. Lentiviral eNOS transduction of cells from CAD patients significantly improved chemotactic migration compared with sham transduction, and increased the ability of CACs to induce angiogenic tube formation when cocultured with human umbilical vein endothelial cells (HUVECs) on Matrigel. In addition, eNOS transduction restored the ability of patient-derived CACs to enhance neovascularization and improve ischemic hind limb perfusion, approaching the efficacy of cells from healthy donors. These data indicate that CAC dysfunction seen in high-risk patients can be partially reversed by eNOS overexpression, suggesting that ex vivo gene delivery may improve the efficacy of autologous cell therapy for cardiovascular disease.