This master's thesis focuses on providing a theory on the practice of financial management and the financial viability of non-governmental organizations or non-profit organizations.Several Non-Governmental Organizations in the Democratic Republic of Congo, as well as in different countries around the world hope to have a good practice of financial management in order to properly execute their projects financed by the various donors. This study was aimed at establishing the effect of financial management practices and the financial viability of nongovernmental organizations. The independent variables of the study were management and financial planning (liquidity, capital budgeting or determination on the capital structure). The main objective of the study was to identify the practice of financial management of nongovernmental organizations and find out some of their financial systems and how they could materialize it.The study used panel data analysis to establish the relationship between financial management practices and the financial viability of non-governmental organizations.