1. We studied the effect of dietary oregano essential oil (50 and 100 mg/kg of feed) on the performance of broilers, and determined the susceptibility of the resulting broiler meat to ironinduced lipid oxidation. 2. Performance of the birds was unaffected by the experimental diets. Therefore, dietary oregano oil exerted no growth-promoting effect on broilers. 3. Iron-induced lipid oxidation showed that as oregano oil increased in the diet, malondialdehyde values decreased in tissue samples, suggesting that the oil, particularly at 100 mg/kg of feed, exerted an antioxidant effect on chicken tissues. 4. Dietary α -tocopheryl acetate supplementation at 200 mg/kg of feed displayed greater antioxidant activity than oregano oil at either supplementation rate. 5. Thigh muscle was more susceptible to oxidation than breast muscle, although the former contained α -tocopherol at higher concentration. Muscle α -tocopherol is an important factor influencing lipid oxidation, but the influence of polyunsaturated fatty acids and content of pro-oxidants must be taken into consideration too.