Relevance. Currently, there is no common understanding and approach to the definition of startup activity, startup, startup project, as well as to the range of their subjects. Many by-laws are adopted in which the concept of a startup and its subject composition contradicts previously adopted similar documents: for each state support program, its requirements for recipients are defined, which prevents equal access of entrepreneurs to economic benefits.The purpose of the article is to determine the range of subjects and distinctive features of startup activity.Objectives. Defining the circle of participants in startup activities; forming the concepts of «startup» and «startup project»; highlighting the main features of startup activities.Methodology. To achieve reliable results, general scientific methods of analysis, induction and deduction, interpretation and systematization of legal norms were used, the formal legal method and methods of generalization of legal norms were also used.Results. In the course of the study, a circle of subjects of startup activity was established, which includes both legal entities and individual entrepreneurs, as well as individuals.Conclusion. Startup activity combines startups and startup projects. If we are talking about startup entities, then we can include legal entities and individual entrepreneurs registered in accordance with the legislation. If we talk about the subjects of a startup project, then the circle of subjects includes mainly individuals who can only plan the launch of their innovative business. The idea may not necessarily develop into a real entrepreneurial activity, since various obstacles may arise on the way to a successful project, such as economic, technological, legal and social factors.