In the present study was aimed to investigate effects on the levels of serum total antioxidant (TAS), oxidant (TOS) and sialic acid (TSA) in Cyprinus carpio (L., 1758) of tebuconazole used as a fungicide. The fishes were kept in tanks for 15 days in terms of adaptation. After, it was formed three groups each containing 6 fishes. Group II and III were placed into separate tanks containing respectively 2 and 3 mg/L tebuconazole and also group I was placed into normal water for 14 days. It were taken the blood samples from fishes and analyzed the levels of serum TAS, TOS and TSA. Even though the serum TAS levels of Tebuconazole-treated groups were lower compared the control group, in terms of TOS and TSA levels was deter-mined the increases. In conclusion, it was determined that tebuconazole treatments caused im-portant changes on the levels of serum TAS, TOS and TSA in carps.