OBJECTIVE: Bone marrow stromal cells (MSCs) are stem cells that can differentiate into chondrogenic, osteogenic, myogenic, adipogenic, and neurogenic cells according to the surrounding environment. Moreover, transplanted stem cells can migrate from the graft site in the recipient brain. The survival and migration patterns of the transplanted MSCs are investigated histologically. METHODS: Bone MSCs were harvested from adult Fisher rats and cultured for several passages. To identify cells derived from MSCs, 5microM bromodeoxyuridine (BrdU) was added to the medium 72 hours before transplantation. Bone MSCs were transplanted into the striatum of the recipient rat stereotactically. Test groups consisted of intracerebral transplantation of MSCs (n=6) and control-cultured medium alone (n=4). BrdU, hematoxylin and eosin staining were performed fourteen days after transplantation. RESULTS: More than 80% of the cultured MSCs showed reactivity to BrdU in vitro. Transplanted MSCs were found mainly around the injection route and migrated from the injection site about 1mm along the white matter. The corpus callosum clearly showed migration of MSCs. CONCLUSION: The results suggest that stem cells can be easily obtained from the adult bone MSCs and the transplanted MSCs can migrate from the grafted site. In such cases, the migration pattern of the grafted MSCs may be determined according to the recipient environment.