Present study was conducted to assess the protein content in various tissues of snake head fish, Channa gachua after sub lethal exposure to chlorpyrifos. Chlorpyrifos is an organophosphate insecticide widely used in agricultural and domestic field for control of the pest. The lethal conc. was found to be 0.05ml/L under laboratory condition and 1/4th of lethal concentration was considered as sub lethal concentration. The acute toxicity of chlorpyrifos on C.gachua was assessed for 24, 48, 72 and 96 hrs. to sub lethal concentration (0.0125 ml/L) i.e. 1/4thconc. of LC50 and changes in protein content of various tissues like muscle, gill, stomach, intestine and brain was studied. The study revealed gradual decrease in protein content in above tissues. Hence, it was concluded that the pesticide intoxication made defective consequences in the normal metabolic pathways which increased the rate of mortality in fish population and risk of biomagnifications in food chain.