Peripheral Artery Disease (PAD) is estimated to effect 8-12 million patients in the United States. The disease is defined by narrowed arteries which reduce blood flow to your limbs, resulting in significant pain while walking. Between 2004 and 2020 the prevalence of PAD is predicted to increase by 43%. Up to 25% of these ischemic patients will progress to develop critical limb ischemia (CLI), which frequently requires amputation and is associated with heightened mortality rates. There are approximately 2 million people in the United States suffering from CLI. Patients suffering from CLI have few effective therapeutic options. Available medications, including anti-platelet drugs, anticoagulants, cholesterol-lowering drugs and beta blockers do not directly address disease cause and mainly treat symptoms. Interventional methods such as angioplasty, stenting and bypass surgery are plagued by low success rates due to restenosis and vessel occlusion. One year mortality in this population is 25% with another 25% requiring amputations above the ankle. Effective regenerative therapies that result in increased and sustained blood vessel formation in the damaged limb and accompanied by prevention of ongoing cell death are few. Treatment with SDF-1 provides a unique opportunity to treat PAD patients with a therapy that will result in improved vasculogenesis and limb salvage.