The present studies investigate the induced effects of two pesticides lambda cyhalothrin (pyrethroid) and monocrotophos (organophosphate) on Rana cyanophlyctis (common skittering frog). Two different concentrations i.e. 0.1 and 1％ were used and cholinesterase activity was observed in liver, kidney and brain of these frogs. It was decreased upto 34.6 and 46.3％ in liver, 25.08 and 57.1％ in kidney and 31.64 and 50.7％ in brain under the effect of lambda cyhalothrin. In the case of monocrotophos treatment, cholinesterase decreased upto 37.7 and 57.7％ in liver,57.5 and 67.5％ in kidney and 47.6 and 65.9％ in brain, respectively.