Women Religious Congregations view financial sustainability as a significant threat to religious life. Financial sustainability is essential for Women Religious Congregations so that they can be empowered and capable of taking on more development ownership activities, even when donor support ceases. Proper management of finances can contribute to the financial sustainability of organizations. This research aimed to establish the relationship between financial management practices (financing, budgeting, cash management, and financial reporting) and the financial sustainability of Women Religious Congregations in Karen, Nairobi Kenya.The study concluded that WRCs can enhance their financial sustainability by strategically managing their financing, budgeting, cash management, and financial reporting practices. The study recommends to WRCs and other nonprofit organizations the practice of developing sustainable internal income-generating activities, enhancing budget competency, effective cash management, using financial reporting software, and annual financial report auditing as essential means of boosting financial sustainability.