A study conducted on 24 fatteners was undertaken to determine the effect of the level of feeding pigs in the first period of fattening on fatty acids profile of their muscles. In animals with body weight (b.w.) of 23 kg, the content of crude fat was similar in all muscles examined. In a lipid fraction of M. longissimus thoracis, M. semimembranosus and heart muscle of pigs with b.w. of 23 kg and 60 kg, analyses demonstrated statistically significant differences in fatty acids profile. In the heart muscle, as compared to the skeletal muscles, the contribution of acids from SFA and MUFA families was lower (p<0.01), and that of n-6 and n-3 PUFA acids was higher (p<0.01). In each of the muscles examined, the contribution of saturated and monounsaturated fatty acids was lower and that of n-6 and n-3 polyunsaturated acids was higher in the animals fed a restrictive diet (75% of the dose fed to the control group) as compared to the fatteners fed semi ad libitum. It affected an increase in the ratio of polyunsaturated to saturated fatty acids in the first group of animals (p<0.01). In fatteners fed a restrictive diet vs. those fed semi ad libitum, the content of total fat was lower in longissimus thoracis and semimembranosus muscles. That dependency was not observed in the heart muscle.