The study included 10 clinically healthy calves (group 1) and 10 clinical cases of dermatophytosis (group 2). The influence of dermatophytosis on some serum biochemical profiles and the antioxidant system was investigated. Serum malondialdehyde (MDA), reduced glutathione (GSH), uric acid, nitric oxide (NO), total sialic acid (TSA), lipid- bound sialic acid (LBSA), total protein (TP), and albumin levels were measured in groups 1 and 2. Calves in group 2 had significantly higher (P < 0.001) MDA, NO, TSA, and LBSA levels, and a higher P < 0.01 TSA: TP ratio; however, GSH and uric acid levels were significantly lower (P < 0.001). There was no significant difference between the groups in total protein and albumin. These findings suggest a relationship between dermatophytosis, the antioxidant system, and lipid oxidation.