The effect of micromanipulation and zona pellucida(ZP) on in vitro viability and development of frozen embryos was investigated for the effective cryopreservation of biopised embryos. The ZP-intact 4-cell embryos and ZP-removed 4-cell embryos were biopised using micromanipulator and micropipette, respectively. Biopsied embryos were equilibrated in M16 containing 3.5M DMSO and 0.25M sucrose for 1.5 minutes and then were ultrarapidly frozen in LN₂. The frozen embryos were thawed at 37℃ and were cultured in M 16 at 37℃ for 48 hours under an atmosphere of 5% CO₂ and 100% humidity. The developmental rate of fresh and frozen embryos was evaluated as percentage of embryo development from 4 cell stage to blastocyst. The results were summarized as: 1) the survival rate of 4-cell embryos ultrarapidly frozen and thawed was 73%. The development rate of survived embryos after freezing was 92%; 2) the survival rate of micromanipulated-embryos ultrarapidly frozen and thawed was 79?. The development rate of survived embryos after freezing was 59%; 3) the developmental rate of the cultured fresh ZP-intact embryos was significantly higher than those of the fresh ZP-removed embryos and fresh ZP-removed biopsied embryos (p$lt;.05); and 4) the developmental rate of the cultured frozen ZP-intact embryos was significantly higher than those of the frozen ZP-removed embryos and frozen ZP-removed biopsied embryos(p$lt;.05).