The aim of the paper is to evaluate the effect of firm size to the economic performance of firm belonging to the raising of swine sector (CZ-NACE 01.460). The economic performance is assessed using multiple- criteria evaluation of alternatives methods where the selected coefficients of the profitability ratios, labour productivity and operating ratio are used as the indicator of economic performance. To assess the relationship between firm size and firm performance, the linear regression model is used. The study uses data collected from the database Albertina CZ Gold Edition for the year 2013 that are provided by Bisnode company and from Business Register. The results showed that the larger firms reached higher economic performance compared with smaller ones. These finding indicates that economies of scale are likely to play an important role in sector of raising swine.