Fifty Polish Large White growing pigs were randomly divided into 5 groups (5 gilts and 5 barrows in each group) and fattened from 50 to 105 kg body weight. The experimental factors were gender and addition of vitamins C, E and β-carotene to the diets. All diets were supplemented with 0.5% CLA. Polyunsaturated fatty acids (PUFA) were observed to decrease in pigs receiving combined vitamins C, E and β-carotene compared with pigs receiving a single supplement of β-carotene (P<0.05). In gilts the level of saturated fatty acids (SFA) was significantly lower and the content of unsaturated fatty acids (UFA) and PUFA was significantly higher than in barrows (P<0.01). A high significant difference (P<0.01) was also found between gilts and barrows in the PUFA/SFA ratio. The CLA concentration was significantly higher in gilts than in barrows (P<0.05). Highly significant sex-dependent differences were found in the content of crude fat, which was significantly lower (P<0.01) in gilts than in barrows. The pH of meat 24 h post-mortem was 5.44 in gilts and 5.55 in barrows (P<0.01). Yellowness (b*) was found to decrease in all experimental groups compared with the control group (P<0.01). There was a tendency towards a lower concentration of tiobarbituric acid reactive substances (TBARS) after 3-month storage of frozen meat in the group receiving supplemental vitamin E and combined vitamins C, E and β-carotene compared with the group receiving β-carotene alone (P<0.05). The vitamin supplements caused significant changes in the vitamin E content of meat (P<0.01): the highest concentration (3.06 μg/g) was found in fatteners supplemented with combined vitamins E, C and β-carotene. The vitamin supplements, including β-carotene, exerted no influence on the vitamin A concentration in meat. No significant interaction between gender and the studied supplements was found.