This study was carried out on the farm specializing in organic pig production on 80 fatteners of the Polish native Pulawska breed, allocated into 4 groups (20 pigs each): EM--entire (uncastrated) males, IM--immunocastrates--males vaccinated with Improvac, CM--surgically castrated males and G--gilts. The highest average daily gains were achieved by the IM group, slightly lower by EM, whereas the lowest by CM and G groups. Content of polyunsaturated fatty acids (PUFA) in intramuscular fat and backfat (10.19% and 10.68%, respectively) of IM was lower (P < 0.05) than in fat of EM (11.4% and 13.20%, respectively), but higher (P < 0.05) in comparison to CM (8.43% and 8.71%, respectively). Vaccination of boars against GnRH has not decreased quality traits of organically produced pork. Furthermore, comparing to meat from surgically castrated males, it resulted in better qualities (lower fat content in carcass, higher PUFA level in fat, better physicochemical meat properties).