Combined radiation and wound injury occurs after severe nuclear accidents that accompany explosions or nuclear attacks. High doses of ionizing radiation can cause bone marrow aplasia and delay wound healing. Combined radiation and wound injury is very complex and is more difficult to deal with than single injuries. Multipotent stem cells that have self-renewal potential and multilineage differentiation capacity are the relevant cells in regenerative medicine. To determine whether multipotent stem cells can have multiple therapeutic effects in vivo, systemic transplantation of cultured dermal multipotent cells was performed in rats with combined radiation and wound injury. The results showed that dermal multipotent cell transplantation promoted survival and accelerated both hematopoietic recovery and wound healing in rats with combined radiation and wound injury. FISH analysis using a Y-chromosome-specific probe indicated that donor dermal multipotent cells could engraft into recipient skin and bone marrow after transplantation. FACS analysis of the proportions of CD2- and CD25-positive peripheral lymphocytes indicated that dermal multipotent cell transplantation did not induce an obvious activation of allogeneic lymphocytes in vivo in 3 weeks. These data indicate that dermal multipotent cell transplantation may provide a new tool for the treatment of combined radiation and wound injuries.