Abstract. Functioning of the electricity market in the context of changes resulting from the adoption of Directive 2009/72EC. The process of shaping common solutions in energy sector proceeded evolutionary beginning from the Þ rst Treaties in the Þ fties of the twentieth century, through the strategic for energy market, legislation enacted in the nineties. In practice, the process of creating an internal energy market can be divided into three stages, which are associated with speciÞ c solutions of a legal nature. The article focus on the latest legal acts that regulates functioning of European energy market. The most important considerations concern on the new directive 2009/72/EC of European Parliament and of the Council of 12 July 2009 concerning common rules for the internal market in electricity and repealing Directive 2003/54/EC. The new legislation strengthens the EU’s internal energy market, give consumers more protection and the beneÞ t of the lowest possible energy prices while offering companies the chance to compete on a level playing Þ eld. In addition the it promotes sustainability by stimulating energy efÞ ciency.