Applications of synthetic pesticides is one of the methods used to increase agriculture production, due to their long term persistence, slow degradability and toxicity affects other organisms.. Present study was carried out to investigate the effect of profenofos on the haematology of the fish Notopterus notopterus. Fishes were exposed at sub lethal concentration of profenofos, thereafter blood was assayed for selected haematological parameters. Reduction in the number of RBC, Hb, and WBC indicating anemia. Whereas increased activity of blood sugar, blood urea, total cholesterol, serum triglyceride, alkaline phosphate, SGPT, SGOT indicated hepatic tissue damage. Decrease in serum uric acid and serum potassium indicates changes in ionic regulations.