A big issue in stem cell research is to derive prospective totipotential stem cells. In this study, fMSC-SSEA-4 cells expressing SSEA-4 anti- gen were isolated from fetal marrow masenchymal stem cells (fMSCs) using immunomagnetic bead sorting technique. The totipotent cells were identified and their biological characteristics were further stud- ied. The expression of Oct-4 and SSEA-4, carcino- genicity, and the ability to differentiation of fMSC- SSEA-4 cells were evaluated to verify the totipotent potential. fMSC-SSEA-4 cells were isolated suc- cessfully from fMSCs (2.5% among fMSCs), while no obvious differences were seen in morphology, growth curve, cell cycle and immunophenotype, Oct-4 and SSEA-4 expression between fMSC-SSEA-4 cells and fMSCs. fMSC-SSEA-4 cells showed normal diploid chromosome karyotype and no carcinoma was in- duced after inoculation into nude mice. fMSC- SSEA-4 cells could be induced to fat cells, osteo- genic cells and neuron-like cells in vitro with different induced factors. The results indicated that there may be a few totipotent cells among the fMSCs and it may offer the experimental basis for the further study and application of fMSCs. A big issue in stem cell research is to derive prospective totipotential stem cells. In this study, fMSC-SSEA-4 cells expressing SSEA-4 anti- gen were isolated from fetal marrow masenchymal stem cells (fMSCs) using immunomagnetic bead sorting technique. Totipotent cells were identified and their biological characteristics were further stud- ied. The expression of Oct-4 and SSEA-4, carcinogenicity, and the ability to differentiate of fMSC-SSEA-4 cells were evaluated to verify the totipotent potential. fMSC -SSEA-4 cells were isolated suc- cessfully from fMSCs (2.5% among fMSCs), while no obvious differences were seen in morphology, growth curves, cell cycle and immunophenotypes, Oct-4 and SSEA-4 expressions between fMSC-SSEA- 4 Cells and fMSCs. fMSC-SSEA-4 cells showed normal diploid chromosome karyotype and no carcinoma was in- duced after inoculation into nude mice. fMSC-SSEA-4 cells could be induced to fat cells, osteo- genic cells and neuron-like cells in vitro with different i nduced factors. The results indicated that there may be a few totipotent cells among the fMSCs and it may offer the experimental basis for the further study and application of fMSCs.