Eight-cell mouse embryos equilibrated with vitrification solution(VS3), consisting of glycerol and polyethlene glycol, were plunged directly into liquid nitrogen. The embryos were cryopreserved by vitrification without intra- and extracellular ice formation. After the vitrified embryos were warmed at 4$^{circ}C$, sucrose dilution procedures were examined and the survival embryos were transferred to recipients after 48h incubation in vitro. The results were obtained as follows. 1. Mouse embryos equilibrated with VS3 were diluted with 1.5m sucrose-HB 1 solution, 0.5M sucrose-HB1 solution for 5min at room temperature, respectively. The proportion of vitrified-warmed embryos developed to blastocyst(85.7%) was as high as that of the embryos diluted with 1.04M sucrose-HB1 solution at 4$^{circ}C$(85.5%). 2. Normal live youngs were obtained in 53.9%(55/102) of the vitrified-warmed embryos after tranfer to pseudopregnant recipients.