This study evaluated the potential protective effect of ferulic acid (FA) on stress induced by imidacloprid (IM) in Cyprinus carpio (mean weight 60.10±2.22 g). Therefore, C. carpio was exposed to sublethal IM concentration (2.80 mg/L) for 10 days. During the experimental period, fish were fed a basal (control) diet and a basal diet supplemented with 5 g/kg of ferulic acid. The fish were divided into four groups (n = 6 in each group). The control group was exposed to tap water (the absence of imidacloprid) fed with control diet. The FA group was exposed to tap water (the absence
of IM) and was fed with FA supplemented diet. The liver and brain tissues of both control and treated fish were dissected. Tissues samples were obtained from an individual fish and prepared for analysis. The variations in catalase (CAT), superoxide dismutase (SOD) activities, and levels of malondialdehyde (MDA) with protein carbonyl (PCO) in liver and brain tissues of C. carpio were investigated in experimental groups. CAT activities were significantly increased whereas SOD activities were decreased in liver and brain tissues of treated fish by exposure to imidacloprid. Tissue MDA and PCO levels in the IM supplemented experimental groups were increased compared to the control. At the end of the experiment, it was determined that FA application had the effect of improving tissue enzyme activities and levels of MDA and PCO.