The article is devoted to actual problems of creating and functioning of special economic zones in the Russian Federation and the Republic of Belarus. The practice of functioning of special economic zones in Russia, including the dynamics of their creation and territorial location is considered. The competitive advantages of special economic zones such as tax incentives for corporate income tax, corporate property tax, land and transport tax, insurance premiums, as well as customs and other preferences are characterized. The results of the functioning of special economic zones considering different aspects are presented: optimistic-from the point of view of the Government of the Russian Federation, pessimistic – from the point of view of the Accounts chamber of Russia, as well as independent experts. The disadvantages and problems of the process of creation and functioning of special economic zones are analyzed, examples of successful functioning of special economic zones of various types – industrial-production, technical-implementation, port are given. The existing methods of assessing the effectiveness of the special economic zones, both official and proposed in scientific research, are regarded. The experience of creation and functioning of special economic zones in Belarus is analyzed. Its advantages in comparison with the Russian experience and general problems are shown. The efforts of the Russian Federation and the Republic of Belarus to improve the business environment and investment climate are illustrated by the World Bank’s business ratings, including the latest rating-Doing Business 2019. The importance of the early solution of all problematic issues in the creation and functioning of special economic zones in connection with the resumption of the process of creating new special economic zones in Russia after a two-year moratorium is emphasized.