In this present study.the ettect of polychlorinated biphenyl (PCB) on fatty liver and some blood parameters in chickens were studied. For this purpose,32 egg type male chickens at 1 day of age obtained from a commercial hatchery were used as materials.Animals were divided into 4 equal groups.First group was keept as control group.The other groups were used as treatment group 1.2,3. and administrated 5,10,30 mg/kg of PCB with food respectively. Animals were fed and watered ad libitum during the experiment 40 days End of the experiment.blood samples were collected heart puncture and after cutting all of the animals liver samples were taken immediately Blood serum cholesterol,triglycerides and AST values were determined spec-trophotometrically(Shimadzu 2100),Na and K levels were performed with Flame Photometer Plasma vitamin A and vitamin E values were measured with HPLC The lipid infiltrations in the cytoplasma of liver pa-ranchymal cells in controtreatment 2 and 3.groups were miid,but the other treatment group was moderate. Cholesterol, triglycerides, AST, vitamin A and vitamin E values were different from control group and found statistically significant(P<0.05).Na and K levels in the groups were not changed statistically As a result.the changing of some blood parameters were correlated with the dose level of 5,15,30 mg/kg PCB The tower levels of PCB were not produced signilicant fatty liver In chickens.