The sugar market in the EU is among the most regulated food markets in the world. This regulation is based on production quotas and foreign trade regulations. Individual links of the marketing chain are characterised by highly varied degree of concentration. Growers of sugar beets and consumers are very numerous and possibly have the weakest bargaining power. The highest degree of concentration is in the sugar industry, which is a classic oligopoly, because four producers manufacture a homogenous product. Thus differentiated structure, faced with strong market protection, creates potential conditions for monopolistic practices and obtaining the so-called monolithic margins. Sugar production and prices in Poland and in the EU are largely conditioned by the system of market regulations. The conducted sugar market reform had little effect on the interrelation of the EU prices with the world prices in the analysed period. As a result of the reform, the relations of the Polish or EU prices to the world prices dropped (this coincided with the growth in the world sugar prices) and, at the same time, there is no growth in the long- or short-terms relations. In 2004, the selling prices of sugar in Poland are linked to the EU prices and their level is not highly divergent from the average prices in the Community. These relations weakened slightly along with the end of the reform and the nature of long-term relations changed. Stronger interrelations are between retail and wholesale prices.