The present investigation was aimed to observe the histological changes in the kidney of Ophiocephalus striatus exposed to LC₅₀ dose (0.72 ± 0.007µl lit ^-1) of Cypermethrin (25% EC) for 96 hours. Kidneys were dissected out to study the histological alterations. Light microscopic studies showed the many his to pahological changes in the kidney. Kidneys were significantly affected showing degenerative and necrotic changes. Vacuolation, glomerular shrinkage, disorganized renal tubules, damage to haemopoietic tissue and blood vessels was observed. Loss of integrity of tubular epithelial cell and interstitial tissue, as well as nuclear pkynosis and karyloysis in renal tubules was prominent in the kidney.