An overview of existing cancer screening programs, their organization system, and the main implementation parameters is presented. The methods of primary screening that have been shown to be effective in reducing mortality from certain cancers, as well as the reasons for the lack of screening programs in relation to some of them, are listed. The existing screening programs and their main characteristics are considered, and examples of using economic analysis to change screening programs are given. It is noted that in countries even with a large coverage, for example, in the United States and Germany, there is no single national register of screening, and the invitation system does not have a population-based nature. Although the large coverage and development of health systems in these countries allows for the positive effects of opportunistic screening, its effectiveness is lower than in countries with organized programs, and the costs are higher.