Abstract: The cryoprotective effect and toxicity of Bovine Serum Albumin (BSA) at 8 concentrations (0, 2, 4, 8, 16, 32, 64, 96 mg/mL, respectively) supplemented in cryoprotectant solutions on mouse pronuclear-stage embryo vitrification were studied. Survival rate, cleavage rate, blastocyst rate and mean cell numbers of blastocyst of vitrified embryos were used as criterion to evaluate the effect of BSA on the post-thawed embryos development. The results showed that no statistical differences of survival rate, cleavage rate, blastocyst rate and mean cell numbers of blastocyst of vitrified groups both in the toxic effect assay (P>0.05) and the vitrification assay (P>0.05). The results indicated that BSA in this cryoprotectant solutions has no effect on the viability of pronuclearstage embryos. Economical, practical and biosecure considerations do not support the use of BSA in vitrificationsolutions.