The aim of this study was to determine the effects of Vitamin E and organic or inorganic selenium sources combined with Vitamin E on growth performance and plasma and tissue glutathione peroxidase activity in broilers. A total of 168, one!day old female commercial broiler chicks (Hubbard strain) were randomly allotted to one control and three treatment groups, each containing 42 birds. All experimental groups were replicated three times with 14 chicks per replicate. Feed and water were supplied during the experimental period. Four experimental diets were provided as follows: a. Basal diet without Vitamin E and any selenium sources, for the control group (control). b. Basal diet supplemented with 250 mg/kg Vitamin E for the treatment group 1 (Vit E). c. Basal diet supplemented with 250 mg/kg Vitamin E plus 0.2 mg/kg organic selenium for the treatment group 2 (Vit E+Or Se) d. Basal diet supplemented with 250 mg/kg Vitamin E, plus 0.2 mg/kg inorganic selenium for the treatment group 3 (Vit E+Inor Se). The experiment lasted 42 days. At the end of the study, there was a difference (P<0.05) regarding body weight gain in the first (Vit E) and the second (Vit E+Or Se) treatment groups compared to the control group. Mustafa SALMAN*, Zehra SELÇUK*, Ö. Hakan MUĞLALI* *Department of Animal Nutrition and Nutritional Diseases, Faculty of Veterinary Medicine, University of Ondokuz Mayis, 55139, Kurupelit / SAMSUN !"# $ %#&"&# ’("!#% ’!)"! $ *& + !*$% ,)# *% JIVS 2007;3:2534 Salman; Selçuk; Muğlalı: Effect of Vitamin E and Selenium