Previous studies on the oxidative stress in swine indicated a strong link between the values of reactive oxygen metabolites (ROMs), the subsequent antioxidant adaptive response (OXY) and the genetic selection. Such findings, mainly related to a cardiovascular inadequacy in lean, large muscle blocks and fast growing breeds, is associated with specific metabolic diseases such as porcine stress syndrome and mulberry heart disease. In this study, we investigated the oxidative stress parameters to trace the genetics of Cinta Senese (CS) pigs, a historical breed free-range reared in Siena countryside. Sera from CS (n = 24) and Large White × CS (LW × CS) (n = 24) groups around 120 kg body weight fed the same diet were sampled at slaughter. Sera from wild boars (WB) (n = 24) hunted in the same district were also considered. ROMs and OXY were evaluated in the three groups of swine. Significant differences by one-way anova (P < 0.05) between groups were found for both procedures. ROM levels were lower in WB (9.79 ± 5.76 mm H2O2) and CS (18.02 ± 7.42 mm H2O2), and highest in LW × CS (42.78 ± 8.61 mm H2O2). OXY values ranged from 271.37 ± 50.90 μm neutralized HOCl (WB) to 343.21 ± 57.45 μm neutralized HOCl (LW × CS). Results indicated that the evaluation of the oxidative stress can effectively trace the CS pigs, thus aiding in preserving the overall specific traits of such a historical animal.