The administration of metformin significantly increased the expression of Sirt3 in oocytes of the metformin-treated mice in comparison with oocytes obtained from the sham group; the relation expression of Sirt3 gene in PCOS + metformin group was 0.59 which is not significantly different with control but at P < 0.05, it was different with PCOS group. This evidence concerns the gene SIRT3 and polycystic ovary syndrome.