This paper identifies and ASSESS total, average and extreme productivity changes regarding labor in commodity farms in Poland in first years of the European Union accession – 2004 and 2005; and also after five years of membership – in the years 2009. The researches were conducted based on data from polish FADN. Survey was made using of Cobb-Douglas production function. The results show that productivity of labor increase in examined rural farms after five years of Poland membership in the EU.