Intramuscular fat occurring in the muscle of cattle is supposed to be prerequisite for high-quality beef. Marbling has effect on juiciness, tenderness and flavor of the meat. Selection of cattle at higher marbling score brings increased meat tenderness. It is influenced by many factors, among which we classify genetic background, age of animal, nutrition, sex and pedigree of animal. The aim is to perform association analysis beetween dinucleotide polymorphism in the gene DGAT1 (diacylglycerol acyltransferase 1) and the marbling score. Part of thesis is elaboration of literature, present state of the problem, genes affecting metabolism of intramuscular fat in cattle, the role of the enzyme DGAT1 in the biosynthesis of triacylglycerols and its physiological function (energy metabolism, glucose metabolism, relation to fat accumulation and obesity). In this study a singificant difference of allelic contribution to intermuscular fat content in tested samples was found. Nevertheless, effect of Q allele was reverse than observed in similar studies.