The aim of this study was to evaluate MYH7 single nucleotide polymorphism (SNP) (NC_010449.4: g.7:75667956G>A) in relation to growth and carcass traits in pigs reared in Poland. Previous study has shown that g.7:75667956G>A substitution in pigs influences miR-208b and MYH7 expression, and is associated with proportion of muscle fibre types. The presented study was conducted on 582 pigs belonging to six breeds: Polish Landrace, Polish Large White, Puławska, Pietrain, Duroc and Hampshire. Statistical analysis (GLM procedure) was performed for first three breeds separately and for whole group together. Our study showed that investigated SNP was associated with test daily gain, average daily gain, age at slaughter and number of days in experiment (P ≤ 0.05 or P ≤ 0.01) in Polish Large White, Puławska and whole group. Among carcass traits MYH7 variants influenced mean backfat thickness from 5 measurements (P ≤ 0.05) in the same groups. We also noticed some associations for slaughter efficiency, weight of loin without backfat and skin, loin eye area and meat percentage (P ≤ 0.05 or P ≤ 0.01) but results were not consistent among breeds and whole group. Obtained results indicate that MYH7 SNP could be used as a genetic marker for improvement of some growth traits and backfat thickness in pigs.