Transformation to a market economy in 1990 year and accession to the European Union in 2004 year had a big impact on the functioning of our agricultural sector and the organisation of farms in Poland. The aim of the paper is try to determine the organisation changes and process of production concentration in Polish agriculture on the background of selected countries in EU. The results indicate that the concentration and specialisation of production is necessary for economic and organisational reasons. This underpins the increase in productivity, improvement of the economic condition and easier sale of agricultural products. Unfortunately, these processes are also associated with an increase in pressure from agriculture on the natural environment.