Introduction: It is now generally accepted that Vero cells provide beneficial effects on improving embryo quality in many animal species. The aim of this research was to determine the effect of Vero cell co-culture on the development of vitrified 8-cell mouse embryos. Material and Methods: Eight- cell mouse embryos were provided from superovulated female NMRI mice and divided into treatment case and control groups. In group oftreatment 8-cell mouse embryos were vitrified by 40% ethylene glycol and the thawing was done in 0.5µ sucrose solution. Vitrified embryos were transfered to MEMa medium or MEMa +Vero cells. The control group which consisted of non-vitrified embryos, were also transfered to the same media. The comparison of developmental rate of both groups were evaluated in MEMa and MEMa +Vero media. Results: Culture of vitrified embryos in MEMa medium indicated that there is an increase in the percentage of hatching, while culture of frozen embyros in MEMa +Vero co-culture medium had no effect on the developmental rate of embryos. Conclusion: Eight-cell stage of mouse embryo is suitable for vitrification and Vero cell co-culture is not necessary for improving the development of embryos.