Beef meat is generally considered a valuable source of nutrients. The quality and nutritional value of beef is determined by the fat content and the content of fatty acids. Beef is a source of desirable omega-3 and omega-6 polyunsaturated fatty acids. Since the quality of the meat and the content of the beef carcass are influenced by genetic and environmental factors, numerous studies have been conducted with the aim of changing and improving the content of fatty acids. Conducted genetic research has hypothesized several potential genes that affect fat storage and metabolism. The aim of the work was to determine the association of FASN, SCD and GH gene polymorphisms with the content of fat and fatty acids in beef. The research was conducted on 104 individuals. For the purposes of the research, Holstein cows were crossed with bulls of four beef breeds (Belgian Blue, Piemontese, Limousin and Simmental), while Simmental, Hereford and Charolais were selected from purebred breeds. The heifers were slaughtered at the age of 14 to 15 months and the bulls at the age of 19 to 20 months. At 24-hour post-mortem processing of the carcasses, conformation and fat coverage was evaluated. The subcutaneous fat tissue thickness was measured with a calliper over the m. longissimus dorsi over the 12th and 13th rib at a point three-fourths of the length of the ribeye from the split chine bone. Approximately 20 g of subcutaneous fat tissue was taken to determine subcutaneous fatty acid composition and total lipids, while 100 g of MLD for the total fatty acid composition. Extraction of DNA was carried out from blood using Blood Genomic DNA kit. Detection of the FASN, SCD and GH polymorphism included PCR amplification and subsequent digestion at 37 °C for 4 hours using MscI, Fnu4HI and Alui restriction endonuclease, respectively. The allele and genotype frequencies were determined, while statistical analysis was performed by general linear model. No significant effect on carcass fat was observed among FASN genotypes. The FASN-AA genotype had the lowest EUROP fat grade, subcutaneous adipose tissue thickness, MLD fat content and fat/connective tissue percentage in 9th -11th part of the ribs. It was not determined that other combinations of genotypes significantly affect carcass thickness and fatness, although the p-values indicate certain relationships where the FASN-AA genotype has a lower carcass fat value compared to the FASN-GG/GA genotypes and the FASN-GG genotype (p=0.153 and p=0.211) and fat in MLD (p=0.438; p=0.366). In the SCD genotype, fat, and connective tissue in the cross-section of the ribs had the highest value in the SCD-TT genotype compared to the SCD-CC and SCD-CT genotypes (TT > CC > CT; p<0.100). However, a significant difference (p=0.049) was observed between SCD-TT versus SCD-CT/CC genotypes and between heterozygous SCD-CT versus SCD-TT/CC homozygous genotypes. EUROP fat grade in GH genotypes had a high level of significance (p=0.053) with the highest proportion of fat in the heterozygous GH-CG genotype (CG > CC > GG). It was also determined that the fat content in the carcass was significantly lower in the heterozygous GH-GC genotype compared to the GH-CC/GG genotypes (p=0.029). A significant difference between the content of fat and connective tissue, with a higher value found in the GH-CC genotype compared to the GH-CG/GG genotypes (p=0.046). Also, a difference was found between the content of fat and connective tissue in the heterozygous GH-GC genotype compared to the homozygous GH-CC/GG genotypes (p=0.034). A significant influence of docosahexaenoic fatty acid was found in FASN-AA genotype (p=0.024), while docosadiene had a significant influence in FASN-GG genotype compared to GA/AA genotypes (p=0.009). FASN-GG genotype had a significant value of SFA (p=0.033) and omega-6/omega-3 ratio (p=0.008). Nondecenoic (p=0.012), eicosadiene (p=0.002) and docosahexaenoic (p=0.005) fatty acids were statistically more significant in the FASN-AA genotype compared to the FASN-GA/GG genotypes, which was evident with nondecenoic acid and in the FASN-GG/AA ratio (p=0.036) of homozygous FASN gene genotypes compared to FASN-AA genotype. comparing only homozygous types of the FASN gene, the FASN-AA genotype had a significant value for eicosadiene (p=0.013) and docosadiene (p=0.005) fatty acids, but also for the ratio of omega-6/omega-3 fatty acids (p=0.014). The SCD-CC/TT genotype had a significant influence of pentadecanoic (p=0.049) and heptadenoic (p=0.020) fatty acids compared to the SCD-TT genotype, behenic fatty acid had a significant influence in the SCD-TT genotype (p=0.002), as well as total shares of PUFA (p=0.043), omega-3 (p=0.042) and omega-6 (p=0.044) fatty acids, while linoleic (p=0.029), α-linolenic (p=0.028) and total shares of SFA (p=0.029) had SCD-CC genotype. The results of the comparison of homozygous genotypes of the SCD gene showed significant values of PUFA (p=0.043), omega-3 (p=0.042), omega-6 (p=0.044) and the ratio of PUFA/MUFA (p=0.039) fatty acids in SCD-TT genotype. GH-CG genotype had a significant value (p=0.039) of palmitic, while GH-GG (p=0.034) had eicosane fatty acids, and GH-CC genotype (p=0.048) omega-6/omega-3 fatty acid ratio. A significant value of palmitic (p=0.018), non-decanoic (p=0.039) and eicosenoic (p=0.010) fatty acids was shown by the GH-GG/GC genotype compared to the GH-CC genotype, which was confirmed by comparing the heterozygous GH-GC genotype compared to homozygous GHGG/CC genotypes where nondecanoic acid had a significant p-value (p=0.040). The results of the comparison of only homozygous genotypes of the GH gene showed a significant value of eicosane fatty acid (p=0.044) in the dominant GH-GG genotype, while the ratio of omega6/omega-3 fatty acids was significant in the GH-CC genotype (p=0.048). This research did not establish a significant increase in the content of saturated fatty acids in the muscle and subcutaneous fat tissue of beef cattle, but a significant influence (p<0.05) of FASN, SCD and GH gene polymorphisms on individual fatty acids and on the total proportion of unsaturated fatty acids was determined. Based on the results of the research in question, it is possible to conclude that more favourable quotients of polyunsaturated fatty acids and ratios of ꞷ-6/ꞷ-3 fatty acids were determined in the meat of the researched animals. The obtained research results are significantly different from the authors mentioned in the paper itself, although the methods used are very similar or identical to those of fellow researchers. One of the possible reasons may be in the allele frequencies and genotypes of the FASN, SCD and GH genes, certainly the sampling itself (number of samples) and the methodology of work and data processing. The explanation of the obtained results of various studies can be that polymorphisms of the FASN, SCD and GH genes did not significantly affect the composition of fatty acids, that the markers are not strong enough (informative) if crossbreeds are used in the research (due to the different frequency of allelic variants), while a small number of breeds and the number of sampled individuals should be increased in order to make the research even more extensive and complex. In any case, this research laid a good foundation for further expansion of the study of the mentioned genes and their influence of polymorphism on the composition of fat and fatty acids in beef meat.