This experiment was designed to determine the effects of CZB medium on in vitro culture of murine embryos obtained from FVB/N. CD-1, and CB6F1 strains. Pronuclear stage embryos were recovered from superovulated and mated females 17 h post-hCG. Two-cell stage block, morula and blastocyst stages were used as the end point of the experiments. There is no statistical difference among strains and media for the development to the two-cell stage. However, more FVB/N embryos (88.3 and 82.4%) than CD-1 (57.4 and 57.1%) and CB6F1 (69.8 and 26.9%) reached the 3-8 cell stage in CZB and M16 media, respectively. CB6F1 embryos developed better (69.8%) in CZB than in M16 (28.9%). Morula development for FVB/N embryos was superior (75.0%) in CZB when compared to M16. Collectively, these data suggest that there are strain differences for in vitro embryo development and the in vitro culture medium has a profound effect on in vitro development.