Various recent studies in both human and laboratory animals have indicated an influential role of glucose and phosphate in embryonic development of different strains and species in various media. So this study was initiated to investigate the effects of different concentrations of glucose (G₀=0, G_l=0.2, G₂=5.5 mM) in the absence (P₀) and presence (P₁=0.39 mM) of inorganic phosphate, designated G₀P₀, G₀P_l, G₁P₀, G₁P_l, G₂P₀, G₂P₁ in M16, CZB and T6. EDTA (0.02 mM) and BSA (4 mg/ml) were added to all media. Mouse embryos (NMRI strain) were cultured from one-cell stage (24-26 h post hCG) for 120 h. Every 24 h, all embryos were scored in each treatment for the stage of development attained during 5 days, and embryos in treatments of T6 were stained to determine final cell number. After 120 h, comparison of hatching blastocyst rate in treatments of T6 did not exhibit differences (56-69%) but the blastocysts from G₁P₁, G₀P₀ and G₂P_l had significantly more blastomere than G₀P₀, G₀P_l and G₁P₀ (90 ± 95, 106 ± 5, 103 ± 4, 140 ± 6, 128 ± 5 and 134 ± 5 respectively). Also after 96 h and 120 h, embryos from the treatments of M16 and CZB that included glucose, had a significantly higher hatching blastocyst compared to embryos developed in free-glucose treatments (after 96 h in M 16, 8-15% vs 0% and after 120 h in CZB 52% vs 1625%). Best results in terms of sustaining development to hatching blastocyst were obtained with T6>CZB>M16. These results show that not only the glucose and phosphate have no inhibiting effect on the development of one-cell NMRl mouse embryos to the hatching blastocyst stage in M16, CZB and T6, but also in the presence of glucose the development and cleavage rates increase.