The milk market is one of the most important commodity markets of agrarian products. In the development of redemption prices of milk in the European Union from 1987 to 2009 it is possible to identify two completely different periods. The first period is defined by the years 1987 to 2006. For statistical evaluation of the price development of that time we used the model of constant seasonality stepwise trend. At this stage we did not identify significant long-term trends, the volatility was based on particular cyclic seasonal fluctuations in feed prices. In the second period (the years 2007 to 2009) the turbulent development is visible, which does not allow a description of the mathematical model. The contribution is a part of the research project MSM 6007665806.