Oxidative stress (OS) is detrimental to sperm functions,and the oxidation reduction potential (ORP) is a good measure of OS as it considers the balance between oxidants and reductants.Total motile sperm count (TMSC) is viewed as the single most important semen analysis parameter that can predict male infertility severity,and its correlation with ORP has never been undertaken.The objectives of this study were to assess the correlation between ORP and TMSC,to identify the ORP cutoff value based on the TMSC result,and to compare this cutoff value with previously reported ORP cutoff values in literature.One thousand one hundred and sixty-eight infertile patients and 100 fertile controls were enrolled.Demographic and semen data of the participants were retrieved and analyzed.Wilcoxon\'s rank-sum test compared variables between infertile men and fertile controls;Spearman\'s correlation assessed the static ORP (sORP)-TMSC relationship for the whole sample and among each group individually.Using a 20×106 TMSC threshold,receiver operator characteristic (ROC) analysis determined the sORP cutoff associated with the highest predictive values.TMSC was significantly negatively correlated with sORP across all participants (r =0.86,P ＜ 0.001),among infertile patients (r =0.729,P ＜ 0.001),and among fertile controls (r =0.53,P ＜ 0.001).A 20-million TMSC threshold determined an sORPcutoff value of 2.34 mV/106sperm/ml to be associated with 82.9％ sensitivity,82.8％ specificity,91.5％ positive predictive value (PPV),68.5％ negative predictive value (NPV),and 82.9％ overall accuracy.Compared with previously reported cutoff values in searched literature,the 2.34 mV/106perm/ml cutoff value identified in our study yielded the highest overall diagnostic accuracy in the evaluation of infertile men.