The rapid industrialization and successful green revolution have introduced a large variety of chemicals into our environment. These chemicals entering ecosystems affect man, animal life, plant life and materials and exert serious health and ecological problems. Among synthetic insecticides, the number of synthetic pyrethroids were produced at the large scale and used by the farming community at the global level. These pyrethroids exert its toxic effect on insect and non target organism.It appears to be the best compromise between the effectiveness and disadvantages of insecticides ,being widely used to control a large variety of agricultural pests . In the present study blood has been used to assess the toxic effect of cypermethrin and cyhalothrin on albino rats. Blood can easily be obtained from the intoxicated rats and status of toxicity can rapidly be evaluated. The results of this study are thought to provide necessary baseline data on blood chemistry and hematology in experimental rats under control and treated conditions.