The reform of the Polish social security system implemented in 1999 was incomplete and chaotic. The consequence of this reform is the deteriorating financial condition of the Social Insurance Fund. Financial management methods can be used to reduce the financial deficit of the Social Insurance Fund. The basic methods of managing social security’s finances include the income method and the cost method. To improve the financial efficiency of the social insurance system in Poland, it is necessary for socio-political reasons to use the cost method. This method involves a reduction in the amount of paid benefits and has already been used in 1999 in pension reform. The aim of the article is to indicate what systemic and parametric changes should be introduced to the Polish social insurance system in order to overcome the existing financial deficit. The research methods used in the article include an economic analysis and an analysis of the literature. In diagnosing the financial condition of the Social Insurance Fund, the system efficiency measure was used as a research tool. The conclusion offers the unification of the system, social protection reform, and the use of Individual Social Accounts as means of improving the financial efficiency of the social insurance system in Poland.