Vitrification, a method of freezing embryos, was tested on different stages of mouse embryo development. The study aimed to see which stage is best for successful vitrification and thawing. They froze embryos at 2-cell, 4-cell, 8-cell, morula, and blastocyst stages. Results showed that all stages survived well after thawing, but 4 and 8-cell embryos had higher rates of blastocyst formation and hatching compared to 2-cell embryos. Vitrifying embryos at the 4 and 8-cell stages was most effective for ensuring good development after thawing. Blastocyst embryos had the highest hatching rate after vitrification. This research suggests that the 4 and 8-cell stages are the most suitable stages for vitrifying mouse embryos.