To better understand the effect of different cooling rate in 2-cell mouse embryo cryopreservation, the vitrification in super-cooled liquid nitrogen (nitrogen slush) was compared with ultra-rapid freezing and slow controlled-rate freezing. The mouse embryo development post-thaw was followed. Laboratory experimental study. Six-eight week old female mice CD-1 (ICR) underwent superovulation with intraperitoneal administration of 5 IU of pregnant mare serum gonadotropin followed by 5 IU of human chorionic gonadotropin (hCG) 48 h later. Females were mated with mature males. Females with a vaginal plug were killed 40 hours after hCG receiving. Two-cell embryos were isolated from oviducts. The embryos were washed and incubated in 50 μl droplets of culture medium (global medium, Vitrolife®) under mineral oil (Medicult, Denmark). The embryos were allocated randomly to four groups. Embryos in group 1 (n = 245) were cryopreserved by exposure to vitrification solution for 2.5 min, then transfer to aluminium foil spoon before plunging into nitrogen slush (-210 °C, cooling rate 40,000 °C/min of 1 μl sample). In group 2 (n = 242), embryos were plunged with aluminum foil spoon in liquid nitrogen (-196 °C, cooling rate 2,500 °C/s) after equilibration in ultra-rapid freezing solution for 2.5 min. For slow freezing (group 3, n = 243), embryos were cryopreserved by programmable freezing (Planer Kryo10/1.7 freezer, cooling rate 250 °C/s) in conventional straw. Non-frozen embryos (group 4, n = 245) were control. Frozen embryos were thawed after preserve in close containers under liquid nitrogen for 2 weeks. They were then cultured in groups of 10-15 embryos in 25 μl drops of global monoculture medium under oil at 37 °C in an atmosphere of humidified 5% CO2, 5% O2, 20% N2. The numbers of survived embryos, further cleavage embryos, hatching blastocyst formation were assessed after immediate thawing, 24, 48 and 72 hours of culture. Fisher’s exact and χ2-tests were used for data analysis. Statistical tests were considered significant at the p < 0.05. Vitrification in nitrogen slush was significantly achieved in higher embryo survival rate (234/245; 96.73% vs 233/242; 96.28%, 166/243; 68.31% in group 2, 3, respectively), further cleavage rate (133/245; 54.29% vs 123/242; 50.83%, 62/243; 25.51% in group 2, 3) and hatching blastocyst formation rate (79/245; 32.24% vs 47/242; 19.42%, 39/243; 16.05%, in group 2, 3) compared with that of ultra-rapid and slow freezing group. Controls had higher further cleavage rate (166/245; 67.76%) and hatching blastocyst formation rate (101/245; 41.22%) than embryos that underwent freezing/thawing. Vitrification in nitrogen slush was demonstrated in effect of higher cooling rate to better improve in embryo cryopreservation. The use of mouse embryos as a model for cleavage human embryo freezing was approved.