The V54L missense mutation within the DECR1 gene, which encodes a mitochondrial 2,4- dienoyl- CoA reductase, was investigated to determine whether this polymorphism is associated with growth rate (daily gains), meat content and selection index in Polish Landrace boars kept under uniform feeding and environmental conditions (one herd). The genotype of 334 boars was determined by PCRRFLP, identifying 112, 162, and 60 boars bearing genotypes CC, CG and GG, respectively. Statistical analysis was carried out by the General Linear Model (GLM) procedure, including fixed effects of DECR1 genotype, sire, and birth season. Significant differences (P<0.01) between boars with CC and GG genotypes were found. Boars with genotype CC showed the highest daily gains (860.7 g ± 46.3), in comparison with boars bearing the GG genotype (841.7 g ± 53.6). The current findings support the hypothesis that DECR1 V54L polymorphism is a promising marker of growth rate in pigs.