The aim of the study is to assess changes in the productivity of the total, average and marginal medium flow of capital in commodity farms in Poland on the example of the years 2004, 2005, i.e. during the first years of accession to the European Union, and after five years of membership, i.e. in 2009, taking into account ensuring a level of productivity of resources in accordance with the welfare of the agricultural ecosystems is a priority. The development was made on the basis of empirical data monitoring unit i.e. Polish FADN. Cobb-Douglas method was used. Using the relationship between the total production of SE131 farm and aggregated factors of production: SE011 labor input and SE270 flow of capital factor productivity was determined variation in the studied years. In studied years it has been shown that the most effective factor in the total production of households was medium flow of capital. The results indicate that the analyzed commodity farms in 2009 compared to 2004 and 2005 increased in the total productivity and decreased in the average and marginal productivity of flow of capital. In the studied years, there has been a reduction in economic efficiency factor of growth capital in commodity farms. This is important, because the productivity of resources in agriculture is an important prerequisite for sustainable development, which is considered the most desirable direction. The analysis has demonstrated the need for the optimal use of factors of production, especially the medium flow of capital. More rational decisions in the management of production factors manifested by an increase in the efficiency of the production process, i.e. maximization of production resulting from the proper allocation of the factors, which in turn causes an increase in the competitiveness of farms. A wide range of bio-economy imposes, to a certain extent, patterns of organization of production in this sector.