The sublethal toxicity of quinalphos on histopathology of tissues such as liver, kidney and gill was investigated in fresh water fish, Labeo rohita exposed to 1/10th of sublethal concentration of the chemical for a period of 7, 14 and 21 days. Though, acute exposure has not resulted in death, it led to many histological variations such as histolysis, lesions, necrosis and vacuolation etc. There are many degenerative changes in the tissues studied suggestive of impairment of normal function when compared to controls.