Three chimeric mice were produced by injecting the embryonic stem cell-CCE cells into the cavity of 3.5 day host blastocysts from Kunming and C57BL/6J mice. By analyses of glucose phosphate isomerase (GPI-1), the results show a contribution from CCE cells in heart tissue of female Kunming chimera. Breeding experiments demonstrated that all chimeric mice were fertile but none of 3 chimeras produced germ line transmission.