By its simplest definition, cohesion policy is the European Union's strategy to promote and support the overall harmonious development of its Member States and regions. Reducing development disparities is particularly important in the functioning of the European Union, which is declaratively reflected in the structural policy it pursues, as well as in the strategic documents that are being created. This issue is particularly important in relation to the countries of Central and Eastern Europe, which are at a much lower level of economic development compared to other countries of the European Union. Joining the European Union meant economic approximation to Western European living standards. Access to the single market has created new business opportunities, triggered huge capital inflows into the new Member States and facilitated their integration into global supply chains. Although a significant gap remains today, it is shrinking at a rapid pace. This paper also pays special attention to the European Structural and Investment Funds, which are the main catalyst in this overall effort of harmonious growth and development. They are implemented within the framework of cohesion policy and are available to all who need it. Despite the fact that cohesion policy aims at more than purely economic convergence, the reduction of regional inequalities in the level of development is mainly measured by the convergence of regional levels of gross domestic product per capita compared to the EU average, labor market trends, foreign cooperation and investment. income convergence, and various others. Among other things, the paper deals with comparative analysis between countries, descriptive data analysis and comparison of budget periods that largely determine the future of cohesion policy and all its components.