The subject of the paper is the issue of rules of being subject to a Polish social insurance by persons conducting non-agricultural business activities. Under the Act of 13 October 1998 on Social Insurance System these law regulations have undergone a significant transformation over the last twenty years. Until 2018, the law regulations were widely criticized, mainly due to the amounts of social insurance contributions, and also due to the low flexibility of social insurance regulations. The Act of 6 March 2018 on the Entrepreneurs Law introduced a number of solutions that made this non-agricultural activity a flexible title of Polish social insurance. The paper also contains an analysis of social insurance eligibility criteria and rules of the overlapping titles for insurance coverage. The paper concludes with possible implications of the current model for the self‑employed insurance in Poland.