Effects of three different doses of endosulfan respectively designated as low, medium and high on cytochrome P450(Cyt.P450), glutathione S-transferase(GST) activity and glutathione content (GSH) of hepatic and extra hepatic tissues of rat were determined after 24 hours of treatment. Endosulfan caused induction of cyt. P450 in liver, lung and brain at all the three doses tested while in kidney, spleen and heart either induction or reduction took place and was unrelated with dosages of endosulfan. Similarly, GST activity significantly changed in extra hepatic tissues while liver GST activity did not record any significant alteration under the experimental conditions. The GSH content also showed changes (increase/decrease) unrelated to endosulfan dosages in different organs. Thus, the effects varied with organ and dosages. As these metabolic parameters are involved in biotransformation of many endogenous molecules as well, the study may throw some light on physiological disturbances due to changes in metabolizing system on one side and organ specificity in toxic action of endosulfan on the other.