Background: Attempts to demonstrate a link between idiopathic recurrent pregnancy loss (RPL) and sperm quality have been contentious. Based on this debate, other factors such as the antioxidant capacity of seminal plasma and the amounts of free oxygen radicals known as seminal reactive oxygen spices (ROS) should be considered. Objective: Evaluation of the role of seminal total antioxidant capacity (TAC), in idiopathic recurrent pregnancy loss. Methods: One hundred men were enrolled. Wife of these men had undergone full gynecologic evaluation and basic investigations of infertility and recurrent pregnancy loss of them were normal. Cases were divided into two groups; group 1 “Recurrent pregnancy loss (RPL) group" composed of 50 male partners of couples who had previously experienced at least two clinical first trimesteric idiopathic miscarriages and group 2 “Control group"; composed of 50 fertile men, with at least one child without assisted reproduction treatments, normal karyotype, normal sperm parameters, and wives who had no history of miscarriage. Results: Seminal total antioxidant capacity was significantly lower in RPL group; 1.25 ± 0.36 vs. 1.75 ± 0.64, p<0.001. Also, there was no significant correlation between seminal total antioxidant capacity and paternal age, BMI and seminal fluid examination. On the other hand, there was positive correlation between it and number of previous abortions. Regarding performance of seminal total antioxidant capacity to predict cases with RPL; statistical analysis of current results showed that AUC was 0.741 (95% confidence interval: 0.641-0.842). At a cut-off point > 1.46, the sensitivity was 70% and specificity was 64%. Conclusion: Seminal total antioxidant capacity is a major contributor to idiopathic repeated pregnancy loss. At cutoff point > 1.46; it had sensitivity 70% and specificity 64% in prediction of cases of RPL.