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This study aimed to investigate the polymorphism of matrix metalloproteinase -3 (MMP-3) gene and its expression in the serum of infertile female patients received in vitro fertilization and embryo transfer (IVF-ET). To do so, 100 women with unsuccessful IVF-ET (IVF^–) and 100 women with successful IVF-ET procedure and clinical pregnancy (IVF⁺) were included. Genetic polymorphism and serum concentration of MMP3 were investigated by ARMS-PCR and ELISA, respectively. The results showed no significant association between MMP-3 gene polymorphism and IVF-ET outcome among the two groups studied. However, a significant decrease in the concentration of MMP-3 serum in the IVF^– group was observed in comparison with the IVF⁺ group (P=0.000002). Moreover, we showed that the serum MMP-3 levels in CC, AC and AA genotypes in the IVF^– group were 33, 65.33 and 86 ng/ml, respectively. In conclusion, while there is no significant difference between MMP-3 promoter polymorphism and IVF-ET outcome between the IVF⁺ and IVF^- groups, a significant decrease in MMP-3 serum levels in IVF^- group was seen as compared with the IVF⁺ group. It could be also suggested that the CC genotype is associated with a decreased level of MMP-3 serum concentration and may be associated with IVF-ET failure.