To elucidate the effects of blastoderm graft for chimeric-fish production on further development, transplantations of upper, lower or entire part of blastoderm were performed onto the animal part of host embryos during the blastula stage in zebrafish. In the case of upper, all resultant chimeric embryos developed normally, while in the lower part, many acephalic embryos appeared. When the entire blastoderm was transplanted, many resultant embryos showed normal phenotype with extra cell-mass, while a few had double axis. vas mRNA, one of the markers of PGCs, also kept the expressions in both donor and recipient blastomeres in transplantation of the entire blastoderm. Donor PGCs were frequently detected at germinal anlagen in histological sections of 6-day larvae developed from transplantations of lower and entire blastoderm, but seldom in those of the upper part. These results might suggest that graft transplantation was effective for production of germ-line chimera, but sometimes caused un-regulaory differentiation of graft cells under the community effect.