© 2021 Informa UK Limited, trading as Taylor & Francis Group.Idiopathic male infertility (IMI) is the absence of a reason to explain a patient's infertility, and it occurs at a frequency of %31. In this study we aimed to investigate the oxidant/antioxidant status of patients with IMI and compare their results to those of healthy controls.A total of 79 patients with IMI (group 1) and 90 healthy individuals (group 2) were included in the study. We used Erel & Neşelioğlu’s thiol/disulfide homeostasis test. Collective and individual measurements of oxidative/antioxidative balance components were carried out by this novel thiol/disulfide homeostasis test. Serum antioxidant (total thiol (toSH), native thiol (SH)) and oxidant (disulfide (SS)) levels of all study participants were measured. The results from both groups were compared and analyzed statistically. After toSH, SH, and SS levels were determined, SS/toSH% and SS/SH% levels for each group were analyzed separately and compared statistically.The toSH, SH levels, and SS/SH%, SS/toSH% ratios were significantly different between the groups (p < 0.05).While antioxidant parameters (toSH and SH values) decreased in group1, oxidant parameters (SS/SH%, SS/toSH%) increased significantly. Although SS values were higher in group 1, the difference was not significant (p = 0.214). The SH cutoff value of 507.15 µmol/L predicted the probability of IMI development with 72.2% sensitivity and 74.4% specificity and toSH cutoff value of 545.45 µmol/L predicted IMI development with 70.9% sensitivity and 73.3 specificity (p < 0.001). Multivariate logistic regression analysis showed that the only independent risk factor for the development of IMI is SH. Patients with IMI had a significant change in their thiol/disulfide homeostasis, which suggests the involvement of this imbalance in the pathophysiology of IMI. Furthermore, these results also support the notion of the involvement of oxidative stress in sperm dysfunction. It also points to the possibility of using antioxidants in IMI treatment. Abbreviations: IMI: idiopathic male infertility; toSH: total thiol; SH: native thiol; SS: disulfide; OS: oxidative stress; ROS: reactive oxygen species; DCF: dichlorofluorescein; MiOXSYS: male infertility oxidative system; MOSI: male oxidative stress infertility; LC: L-carnitine; LAC: L-acetylcarnitine; Vit: vitamin; OAT: oligoasthenozoospermia; TMSC: total motile sperm count; WHO: World Health Organization; BMI: body mass index; DTNB: 5,5ʹ‐dithiobis‐2‐nitrobenzoic acid; CV: coefficient variation; ROC: receiver operating characteristic; PR: progressive, NP: non-progressive.