Objective: To study the hematological parameter hemoglobin, total leucocyte count and biochemical parameter serum cholesterol, serum glutamate pyruvate transaminase in fish Clarias Batrachus exposed under different concentrations of Malathion pesticide. Methodology: This experimental research study has been done in teleost fish Clarias Batrachus, exposed 24 to 96 hours, to four different concentrations of Malathion pesticide. Estimation of serum cholesterol and SGPT had been done as biochemical parameter and Hemoglobin as well as T.L.C had been analyzed as hematological parameter. Results: There were no significant changes in hemoglobin level at lower concentration of Malathion pesticide within short intervals but at high concentrations, lowering in hemoglobin levels had been observed at all time intervals though elevated total leucocyte count had been observed at all concentrations and time intervals. Regarding to biochemical parameters significant increase in serum cholesterol and SGPT enzyme levels observed in Malathion pesticide exposed fishes.