This study was conducted to investigate the effects of the carbaryl insecticide on blood parameters and oxidative stress in Cyprinus carpio. A total of 60 fish were randomly assigned to three groups: the first group served as the control; the second group was placed in tanks containing water with a carbaryl concentration of 5mg per liter; and the third group was raised in tanks with a carbaryl concentration of 7.5 mg per liter. The fish were monitored for 14 days. The results showed a decrease in RBCs, hemoglobin, and PCV, along with an increase in WBC count in the experimental groups compared to the control group. Additionally, the study found a significant decrease in GSH and a significant increase in MDA in all experimental groups compared to the control group. The findings suggest that carbaryl has harmful effects on fish, as evidenced by changes in blood parameters and antioxidant indicators.