Objectives. Autologous bone marrow implantation (BMI) is effective to treat critical limb ischemia, but the long-term prognosis is not clear. The outcome of BMI treatment for ischemic legs was investigated related to the clinical background of the patient, and short-term effects of BMI. The end event was defined as unexpected lower limb amputation. Methods and Results. This study included 21 consecutive patients (mean age 60.0 ± 13.6 years) with peripheral arterial disease who underwent BMI between December 2001 and March 2005. Twelve patients had arteriosclerosis obliterans (ASO), 5 had Buerger disease (thromboangiitis obliterans), 3 had thromboembolism, and 1 had hypereosinophilic syndrome. The patients with ASO had severe complications such as diabetes and hyperlipidemia. The total number of transplanted CD34-positive cells, ankle-brachial pressure index (ABI), and tissue oxygen pressure (TcO 2) were lower in ASO patients than non-ASO patients. Significant risk factors for the event were diagnosis of ASO and low TcO2 (&lt
30 mmHg) according to the Kaplan-Meier survival curve and log rank test. All 6 patients who required limb amputation had ASO simultaneously with low TcO 2 (6 of 9, 67%). In contrast, there was no correlation between the end event and short-term effect of BMI such as improvements in ABI and TcO 2. Conclusions. Treatment with BMI could not save legs in some patients with ASO associated with severe leg ischemia.