This work was conducted in order to investigate the impact of herbicide thiobencarb on Clarias gariepinus (C. gariepinus) immunity. Lethal concentration 50 (LC50) was detected, it was 160 µg.l-1 . Four groups were distributed in 12 glass aquaria 1st water had no addition 0% control, 2nd 5%, 3 rd 10% and 4 th 15% of thiobencarb LC50. LC50 96 hours was 160 µg.l-1 . the highest thiobencarb residue was detected in gills followed by liver while muscles had the lowest residues. Thiobencarb chronic toxicity had an impact on SR% and it was decreased in linear manner 86.7, 73.3, 63.3 and 46.67 respectively. Haemogram of C. gariepinus RBCs WBCs HB and PCV MCV was decreased and MCHC had the same trend of HB and PCV while thiobencarb had no effect on MCH. Liver enzyme AST and ALT showed significant increase parallel to increased thiobencarb concentration and TP had decreased while Cholesterol and creatinine had a significant increase. Antioxidant activities GPx and CAT of C. gariepinus showed a significant increase along with increased thiobencarb concentration. Immune of C. gariepinus was drastically impacted as showed in glass adhesion test and serum bactericidal activities test. It was concluded that thiobencarb had an adverse effect on C. gariepinus health and anti oxidant (GPx and CAT) could be used as bioindicator for toxicity.