Purpose: Efficient and secure collection of CD34+ cells are crucial for the angiogenic therapies. We have developed autologous peripheral blood-mononuclear cell (MNC) transplantation induced by erythropoietin (rhEPO) for critical ischemic limbs. Methods: Seven patients, including five with arteriosclerosis obliterans, one with Buerger's disease and one with progressive systemic sclerosis, underwent ten cell therapies. The first administration of rhEPO was performed two weeks before apheresis, and the second administration and blood donation were performed one week before apheresis to activate bone marrow. MNCs including CD34+ cells, isolated from peripheral blood by apheresis, were immediately injected intramuscularly into ischemic limbs. Results: The number of peripheral blood-CD34 + cells had significantly increased from 1.32 ± 0.83/microL, before the rhEPO induction, to 1.86 ± 0.94/microL, before the apheresis. The number of transplanted MNCs ranged between 0.5 × 10 9 and 16.5 × 10 9 , and that of CD34+ cells, between 0.1 × 10 6 and 12.7 × 10 6 , accounting for 0.02%-0.1% of MNCs. There were no serious complications. Finger ulcers with Buerger's disease were significantly improved one month after the transplantations, but the same or other ulcer(s) appeared 2-6 months later. Three patients had an improvement in rest pain, and one patient extended maximum pain-free walking distance. Conclusions: Erythropoietin-induced autologous peripheral blood-MNC transplantation is a useful and safe alternative for ischemic limbs.