Deltamethrin is an insecticide belongs to a group synthetic pyrethroids. The current investigation includes histopathological alteration in the liver, kidney, testis and ovary of Clarias batrachus exposed to a sublethal concentrations (0.015 ppm conc.) of deltamethrin for 30 days. The induced fish showed significant histopathological changes viz. in liver histology showed degeneration, necrosis and hyperemia, testes histology showed spermatogonia cell’s number reduce and condensed, inflammation of cells, tubules vacuolization, and ovary showed follicular cells disruption, epithelial cells degeneration resulted vacuolation, disrupted oogonia with breakdown of germinal vesicle. The present study revealed that deltamethrin affects the fish, Clarias batrachus (Bloch.) at very low concentration.