The aim of this study was to determine thiol/disulfide homeostasis in cattle with trichophytosis and to determine the changes in malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px=GPx) levels due to the disease. 15 cattle with trichophytosis and 15 healthy cattle in the control group constituted the material of the study. Blood samples were taken from the jugular vein of the animals in tubes with and without anticoagulant. MDA, CAT, SOD, total thiol, native thiol analyses were performed in serum and GSH-Px analyses were performed in plasma. It was determined that total thiol, native thiol and native thiol/total thiol levels among biochemical parameters in cattle with trichophytosis decreased statistically significantly. It was determined that disulfide/native thiol and disulfide/total thiol levels increased statistically compared to the control group. Although the disulfide level increased compared to the control group, it was not statistically significant. In addition, it was determined that MDA level increased compared to the control group, CAT, SOD and GSH-Px levels decreased statistically significantly compared to the control group. In conclusion, the findings obtained from the study showed that trichophytosis causes oxidative stress in cattle, and the use of oxidative stress markers, especially thiol/disulfide homeostasis markers, would contribute to the pathogenesis of trichophytosis.