Cryopreservation is a method of reproductive technologythat is useful for embryo and preservation creaturesthat are almost extinct. Cryoprotectants are often used for vitrification are PROH, DMSO and EG becausethey have good and efficient results. The study objectivewas to know does the viability of mice blastocystincrease with the combination of intracellularcryoprotectant ethylene glycol (EG) and dimethyl Sulfoxide (DMSO) in vitrification. This study used mice oocytes thencarried out in vitro fertilization and cultureduntil reaching the blastocyst stage. The mice weresuperovulated using 5 IU PMSG and 5 IU hCG after 48hours, then monomatting using infertile males. Egg cellsare taken by tearing the fertilization bag andwashing using MEM. Embryo is cultured so that it reaches the blastocyst phase and is then divided into 4groups: vitrified using 30% EG, 30% DMSO, 20% combination EG + 10% DMSO and 10% P4 combinationEG and 20% DMSO. The four groups were inserted intothe hemi straw which has been modified with 0.25berurn and then put back into the hemi straw with a size of0.5. Hemi Straw which already containedembryos was inserted into a liquid N2 container with a temperature of -196. Warming was done after theembryo was vitrified for a week. After being removed from the container, heating is done at roomtemperature. The embryo hemi straw was inserted into the sucrose level alternately, i.e. 0.25 M, 0.5 M and1M respectively for 2 minutes. Warming process to removecryoprotectants that are in the embryo.Examination of the viability of blastocyst was done usingan inverted microscope. The results of this studythat there were significant differences between groupsusing combination cryoprotectant EG 20% and DMSO10% (p<0.05) with 84% viability. The combination of EGand DMSO could increase the viability of miceblastocyst. The ethylene glycol 20% and dimethyl Sulfoxide 10% was the best concentration combinationbased on this research.