The composition of selected cuts of cattle carcasses was determined in connection with the search for new methods of carcass classification. The content of adipose tissue and intramuscular fat in the cross-section of beef loin was estimated. A total of 79 samples was taken for investigations in a broad range of cattle category. The classical extraction method in Soxhlet extractor was compared with video image analysis, which measured the ratio of muscle to fat areas. The size and the shape of the musculus longissimus lumborum et thoracis (MLLT) and its ratio in the loin cross-section was also estimated. A good correlation (r = 0.99, P < 0.05) between both methods was found for the estimation of intramuscular fat in MLLT. The correlation in the case of the whole cross-section was influenced by the connective tissue that gives also white areas similarly like the adipose tissue, but the fat content is different.