This bachelor thesis is focused on a monetary policy which was applied by the Federal Reserve System in a period of economic crisis which started in 2007. In the theoretical part of the thesis is mentioned the definition of monetary policy, its tools and facts about the Federal Reserve System. The thesis describes slightly the beginning of a crisis. Then there are described tools, especially tools for providing liquidity to the finantial sector and a communication with public. In a next part of the thesis there is described a quantitative easing, its principles, periods and impacts on a balance sheet of the Federal Reserve System. In the last part, there is analysed the influence of monetary policy on economy of the United States of America