Trichophytosis which caused by Trichophyton spp. is an enzootic skin disease. In this study, effects of trichophytosis on serum adenozine deaminase (ADA) and nitric oxide (NO) activities were investigated. Thirty cattles with thrichophytosis and 10 healthy cattles were used in the study. Average ages of the cattle were 1-3 and average body weight was 250 kg. Blood samples were taken from vena jugularis of the animals. Serum ADA activities and NO levels were detected with spectrophotomethric method. Serum ADA activities were detected 12.70 U/L and 24.49 U/L in research and control groups respectively. Statistically difference was important between two groups (p<0.001). NO levels were determined 34.24 mu mol/L and 36.17 mu mol/L in research and control groups respectively. However, no significant statistically change was determined in this parameter between two groups (p>0.05). Consequently, we thought that, serum ADA levels might be increased by cell mediated. immune system which was stimulated by T. verricosum. Although, NO levels were monitored slightly increase in research group. We thought that, this increase related to newly iNOS release and NO producing in macrophages.