Thalis 112 EC is the trade name of a binary insecticide (Emamectin benzoate 48 g/L, Acetamiprid 64 g/L) used in cotton growing in Benin. These compounds can lead to extensive side effects on the inhabitants living in that exposed area. The present study aims to evaluate the effects of chronic exposure to this pesticide on the immune status of Clarias gariepinus. Thus, 300 juveniles of C. gariepinus (average weight 30.0 ± 2.64g) were exposed in glass aquariums to sub-lethal concentrations of Thalis (T0 = 0.0; T1= 0.03; T2 = 0.06; T3 = 0.12; T4 = 0.25 and T5 = 0.49 ppm) for 28 days. The stocking density is 14 fish per tank filled with 25 L of test solution. The test took place in a semistatic system with 50% renewal of the test solutions every 48 h. It appears from the study that the presence of Thalis leads to an increase in WBC in C. gariepinus. As for Total immunoglobulin, the presence of a low concentration (T1) of the pesticide leads to an increase followed by a decrease as the concentration increases. However, Thalis did not induce a significant effect on PCV, Hb and Erythrocyte constants (MCV, MCH and MCHC), even though Hb and these Erythrocyte constants showed an increasing trend. The RBC also showed an increasing trend. This haematological profile obtained with C. gariepinus exposed to Thalis is probably linked to the binarity of this toxin made up of molecules from various families whose modes of action are different. It is concluded that indiscriminate use of such pesticides poses a noxious threat to non-target organisms, harm the ecosystems and jeopardizes human health.