The effect of grain source (wheat or maize), sex (boars or gilts) and live mass (85 or 120 kg) on the fatty acid composition of backfat was studied on 40 ad lib. fed Landrace x Large White pigs. A highly significant (P<0,001) difference in linoleic acid concentration between dietary treatments was found. Sex had only an influence on the myristic acid content while live mass had a significant effect upon backfat composition.