The aim of this study was to provide a comparative analysis of chemical and fatty acid composition, as well as of the connective tissue proteins in pigs of different genotypes, Mangalitsa and Landrace. Both pig genotypes were fed with the same feed of standard composition and quality. At the end of the fattening period, in total 24 pigs of both genotypes were slaughtered. Based on the analysis of the chemical composition we came to the conclusion that the protein content in both genotypes was similar. Moisture and ash content in the Landrace pig genotype differed significantly (P < 0.01) compared with genotype of Mangalitsa breed. Statistically significant differences (P < 0.01) were established in the fat content, which was 7.95 g/100 g, in pigs of Mangalitsa breed and 1.59 g/100 g in the Landrace pigs breed. Content of hydroxyproline, non-proteinogenic amino acids, in meat of Landrace was significantly higher (P < 0.01) compared to the content in the Mangalitsa breed. The same tendency was observed with regard to the connective tissue protein content, as well as with the relative connective tissue protein content. The fatty acid composition of the meat indicated that the most common saturated fatty acid (SFA) in both tested breeds was palmitic fatty acid (C16), whose content was significantly higher in Landrace (P < 0.01) compared with its content in Mangalitsa breed. In addition, the share of stearic acid (C18) was significantly higher (P < 0.01) in Landrace compared to Mangalitsa pig breed, what significantly contributed to the increase of the SFA share in Landrace compared to Mangalitsa breed. The most common monounsaturated fatty acid in both pig breeds was the oleic fatty acid (C18:1), whose share was significantly higher in Mangalitsa compared to the Landrace breed (P < 0.01). Out of the polyunsaturated fatty acids (PUFA), linoleic fatty acid (C18:2) was the most predominant in both pig breeds, with no statistically significant differences (P > 0.05). The content of PUFA was not statistically significantly different between the tested breeds, as well as the content of n-3 and n-6 fatty acids, which caused no statistically significant differences in the n-6/n-3 PUFA ratio. Ratio of the unsaturated fatty acids, i.e., of the sum of MUFA and PUFA, and of the saturated fatty acids was significantly higher in Mangalitsa compared to Landrace breed (1.86 vs. 1.4), and the same was observed when it comes to the relationship MUFA/SFA (1.51 in Mangalitsa vs. 1.08 in Landrace breed) and MUFA/PUFA (4.35 vs. 3.38).