Introduction:Adipose tissue derived stem cells(ASCs) were very potential and effectives on damaged tissue regeneration. We performed intramuscular multiple injection of ASCs to patients with critical limb ischemia which was composed of DM foot, Buerger���s disease and ASO. Methods:The study comprised 16 patients (16 men) with a median age of 52 years (range, 24-73 years) who had critical limb ischemia.The patients received intramuscular multiple injections of ADSCs into the leg(n=16). Primary end points were avoiding major or minor amputation from baseline to 6 months follow-up, and the safety and feasibility of the treatment. Secondary end points were the changes in ankle-brachial pressure index and claudication, peak walking time, thermography finding, the angiographic evidence of collateral vessel formation or remodeling. ASCs were isolated from adipose tissues of Buerger���s disease patients (B-ASCs) and healthy donor (control ASCs) by 0.075% collagenase digestion. In order to CFU assay, ASCs were plated in a 10mm culture dish at a density of 60 cells/dish. The cell numbers in each colony were counted after 1week. Adipogenic differentiation was assessed by the use of an Oil Red O stain as an indicator of intracellular lipid accumulation. Osteogenic differentiation was estimated by Alizarin red S stain of extracellular matrix calcification. Results:Intramuscular multiple injection of ADSCs was not associated with any complications. The mean follow-up time was 5.2 months (range, 3 to 6 months). Two patient required toe amputation during follow-up. There were no interval change in the ankle-brachial pressure index during 6 months. At 6 months, patients demonstrated a significant improvement in pain scores, peak walking time, claudication walking time, themography finding. Digital subtraction angiography studies before and 6 months after the ASCs implantation showed numerous vascular collateral networks had formed across the affected arteries.B-ASCs showed lower proliferating ability than those of control ASCs. In a CFU assay, B-ASCs displayed lower colony numbers and cell numbers per colony than ASCs. Cell counting at the indicated days after plating of 5 x 103 cells/well showed that B-ASCs had slower growth than control ASCs. However, there was no difference in adipogenic and osteogenic differentiation between B-ASCs and control ASCs. Conclusions:Intramuscular multiple injection of ASCs could be a safe alternative to achieve therapeutic angiogenesis in patients with critical limb ischemia which was composed of DM foot, Buerger���s disease and ASO and critical limb ischemia refractory to other treatment modalities.