Cypermethrin is synthetic pesticide and very toxic pollutant, accumulated in aquatic ecosystems. Present study was designed to investigate acute toxicity of Cypermethrin on Walking Catfish Clarias batrachus. The effect of Cypermethrin on total protein in muscle was estimated in Walking Catfish C. batrachus. Fishes were exposed to different sub-lethal concentration of Cypermethrin (0.07µl/lit) for 1 day, (0.014µl/lit) for 5 days and (0.007µl/lit) for 10 days time intervals. The total protein level was found to decrease as 0.106±0.04, 0.209±0.003 and 0.640±0.02 mg/gram in muscle tissues at different exposure period.