Fluazifop-P-butyl is a commercial herbicide commonly used in agricultural practices for controlling grass weeds. The present work aimed to detect and compare the deleterious changes that may occur in the kidney of the African catfish, C. gariepinus under the different concentrations of fluazifop-P-butyl, as well as studying the histopathological changes in the kidney of exposed fishes to different levels of the selected pollutant.  Fish were exposed to different concentrations (1.72 & 0.57 mg/L)  of fluazifop-P-butyl for different periods (14 and 28 days). At the end of the exposure time, the levels of uric acid, creatinine and urea were measured in the blood serum to determine kidney functions. In addition, a histopathological examination of the kidney was performed to assess the impact of fluazifop-P-butyl on its tissue structure. The results showed that exposure of catfish Clarias gariepinus to fluazifop-P-butyl led to a significant increase in the levels of uric acid, creatinine, and urea in the serum, indicating impairment in kidney functions. The histological examination revealed pathological changes in the kidney structure, including degeneration of renal cells, atrophy of renal tubules and interstitial fibrosis. The findings of this study highlighted the importance of considering the potentially toxic effects of fluazifop-P-butyl on aquatic organisms upon using this herbicide in agricultural practices.