These studies were carried out to improve the reproductive efficiency through embryos transfer ofHanwoo IVM/IVF embryos. Following routine IVM/IVF procedure, Oocytes and zygotes were cultured for40 to 44 h in CR1aa medium with BSA. Then 2 to 8-cell embryos were removed the cumulus cell and werecultured in CR1aa medium containing 10% fetal bovine serum and 2.5 mM taurine in 5% O2 and 5% CO2at 38.5℃. The fresh and frozen thawed embryos of the morulae and blastocysts cultured for 6 to 9 daysin vitro were transferred into recipients. The pregnancy rates of the blastocyst produced for 6, 7, 8, and9 days in in vitro culture were 41.9, 48.6, 57.9 and 47.4%, respectively. In the developmental stage,pregnancy rates of early blastocysts (41.7%), blastocysts (57.6%) and expanded blastocysts (50.0%) werehigher than that of morulae stage (00.0%). Fresh and frozen embryos on the pregnancy rates were 48.9 and50.0%, respectively. These results indicate that the pregnancy rate after transfer were affected on embryonicstage of in vitro embryos and in vitro culture periods.