Winter oilseed rape (Brassica napus), a crucial crop in temperate regions, is a key contributor to global vegetable oil production and an essential component of crop rotations due to its ability to improve soil structure and fertility. Enhancing its yield is vital for meeting the increasing demand for sustainable oil production, supporting food security, and optimizing biofuel production, while also ensuring the economic viability of agricultural systems in colder climates. The aim of the research was to determine association between SNP molecular markers and rapeseed yield. The plant material for this study consisted of 276 oilseed rape hybrids. The experiment was conducted in four localities: Borowo, Kończewice, Małyszyn, and Strzelce. The mean yield values ranged from 0.07 kg (for hybrid EH_20212 in Małyszyn) to 9.10 kg (for hybrid EH_20410 in Kończewice). The genotype matrix for 276 hybrids was constructed using marker data from the parental genotypes of inbred individuals (maternal and paternal lines). The matrix was coded as {- 1, 0, 1}, assuming an additive effect of the alleles. A total of 13,116 SNP markers were identified. For association mapping, 12,581 polymorphic markers were used. The results of the observation of the yield and sequencing were used for association mapping, which ultimately resulted in the selection of twenty-six molecular markers important (LOD >
5.0) simultaneously in all four localities.