The present study was conducted in eight week old male and female Wistar rats. Twenty four male and twenty four female wistar rats were randomly divided into four different groups, Group I, II, III and IV comprising six male and six female rats. Group I served as vehicle control and treated with corn oil. Group II, III and IV served as treatment group and treated with Bifenthrin at dose rates of 2.5, 10 and 20 mg/kg body weight respectively for 28 days daily in corn oil. After 28 days continuous exposure period blood sample was collected on day 29 to study effect on various hematological and biochemical parameters. Bifenthrin, a synthetic pyrethroid insecticide significantly altered hematological parameters (MCV and MCH) in male treated rats. Similarly there was significant increase in serum aminotransferases (ALT, AST), alkalne phosphatase (ALP), creatinine (CRT), urea and glucose levels in treated group of rats as compared to concurrent control group of rats in both sexes. Serum potassium electrolyte level was significantly decreased in male treated rats. Based on these study findings, it was concluded that Bifenthrin significantly altered the hematological and biochemical parameters in wistar rats after four weeks repeated oral exposure.