The effect of linseed oil and α-tocopheryl acetate on the fatty acid composition and the susceptibility to oxidation of lipid fraction from pork tenderloin (Psoas major) muscle has been studied. Muscles were obtained from animals fed on diets with the same ingredients excepting the oil source [sunflower (C), linseed (L) and linseed and olive (1/1, w/w) (LO)] and α-tocopherol [20 (C, L and LO) or 200 (LOE and LE) mg/kg diet]. The n-6/n-3 ratio in pork tenderloin was markedly modified by dietary linseed oil administration, which was due to the increase in the C18:3n-3 (and total n-3 fatty acids) and the decrease in the C18:2n-6 (and total n-6 fatty acids) contents (P<0.05). The α-tocopherol content of tenderloin from batches LE and LOE was about 2.8 mg/kg of muscle, significantly greater (P< 0.05) than about 0.7 mg/kg muscle found in tenderloin from pigs receiving C, L and LO. Dietary supplementation with α-tocopheryl acetate markedly reduced tenderloin lipid oxidation from animals fed diets enriched in n-3 fatty acids (L or LO vs LE or LOE). © 2003 Elsevier Ltd. All rights reserved.