The aim of the feeding trial was to compare the effects of four different dietary fat supplementations (2.5% of tallow, olive oil, soyabean oil or linseed oil), three sire breeds and both sexes upon pig growth and usual carcass traits, but especially upon several meat and fat quality traits. Ninety-six weaners from different German and foreign sire breeds were tested for their ability to improve the quality of market products. The experiment was carried out with 48 barrows and 48 female growing/fattening pigs. They were progeny of German hybrid sows mated to Duroc, Hampshire × Duroc crosses or Pietrain × Hampshire crosses. The animals were individually kept from 30 to 120 kg liveweight. Growth and slaughter performances of pigs were not significantly influenced by the supplemented fat source. The overall mean of intramuscular fat of loin reached only 1.3%, varying between the sire breeds. The fatty-acid composition of backfat and intramuscular fat showed much smaller differences between sire breeds and sexes than between fat supplements to the diets. There were strong correlations between intake (x) and concentration of polyunsaturated fatty acids in backfat (y=3.73 x - 0.91; r²=0.85). Similar correlations were calculated for oleic acid. The results demonstrate that the fatty-acid profile in backfat and muscle can be substantially influenced by fat sources in the diet.