Abstract: The article investigates the financial sustainability and revenue structure of the Pension Fund of Ukraine (PFU) under conditions of economic instability, demographic challenges, and the ongoing consequences of war. Particular attention is paid to the dynamics of own revenues and budgetary transfers, the role of the Unified Social Contribution (USC) as the core source of income, and the systemic risks associated with fiscal dependence on the state budget. Based on statistical analysis for 2014–2024, the study identifies the key trends in PFU revenues and expenditures, highlighting the predominance of state transfers in covering the deficit and the limited capacity of self-financing. The research emphasizes that despite the nominal growth of pension contributions, the effectiveness of resource mobilization remains constrained by a high level of labor market shadowing, declining official employment, and structural disproportions in the economy. The article outlines the macroeconomic and demographic factors influencing PFU performance, including migration flows, aging population, and wartime losses, which intensify the fiscal burden and reduce the flexibility of the pension system. Methodologically, the study applies comparative and statistical analysis to assess coverage, selffinancing, and budget financing coefficients, which reveal the systemic dependence of the Fund on external support. The findings underline the need for strategic reforms aimed at expanding the USC base, reducing informal employment, introducing the funded pension tier, and optimizing expenditures through the revision of special pensions. The conclusions stress that ensuring long-term sustainability of the PFU requires a balanced combination of fiscal stability, institutional modernization, and compliance with international standards of pension autonomy and social protection.