The aim of this final paper is to analyze contributions as a type of public revenue with special emphasis on the importance of contributions for pension insurance. Pension insurance contributions are a type of parafiscal benefits, the basic task of which is to finance the pension insurance system. Contributions first appeared in 13th century England, but Prussian Chancellor Bismarck is considered to be the "father" of social security contributions. In Croatia, social security contributions date back to 1922, when King Alexander I Karadjordjevic introduced the Law on Social Insurance for workers. Today in Croatia, pension insurance contributions are divided into mandatory pension insurance contributions from the first pillar (15%) and mandatory pension insurance contributions from the second pillar (5%). Although each country has a differently regulated pension system and with different characteristics, all countries around the world have in common that contributions are the basic income for financing pensions. By analyzing income, insured persons, pension beneficiaries and types of pensions, we can see that the most problematic ratio of pensions and insured persons in the Croatian pension system is the insufficient inflow of income from contributions for financing the payment of pensions. The Croatian pension system is still burdened with numerous problems, so we can conclude that the Croatian pension system urgently needs a comprehensive pension reform.