The main aim of the thesis is to perform the financial analysis of company E.ON Energie, a.s. based on the accounting data from 2006-2010, to critically assess the development of the data and important ratios and to compare the results with the best company in the industry sector. The thesis is divided into two main parts: the theory and the practical application. The theory explains the methods that I decided to choose for the financial analysis -- horizontal and vertical analysis, ratios of profitability, leverage, liquidity and activity, the DuPont analysis and selected bonity and bankruptcy models. In the theoretical part I also assess the explanatory power of financial statements and its main threats. In the practical part I present the company as an electricity and natural gas retailer. The energy industry has recently undergone a market liberalization, which had a large impact on the energy companies. As the sector analysis of Michael Porter confirmed, the industry faces greater competition than before. The energy companies are also influenced by macroeconomic developments, e.g. GDP and energy consumption, prices in the electricity market and the euro exchange rate. The main result of the performed financial analysis is the fact that E.ON Energie, a.s. follows its strategy to become a leader in the electricity market. In the years 2009 and 2010 E.ON Energie, a.s. caught up with CEZ Prodej, s.r.o. in the liquidity, leverage and activity ratios. In addition to this, it improved its profitability. Moreover, the revenues grow at a faster pace than in CEZ Prodej, s.r.o. In the future it will be interesting to see how the company will develop despite the increasing competition in the market.