In spite of the fact that the waqfs have existed with the history of humankind and are helpful in all social communities, they have a different and important place in Islamic societies. The waqfs have institutionalized and organized assistance and solidarity between individuals. Especially in Islamic so­cieties, a great importance has been attached to waqfs. The waqfs that helped institutionalize the concept of “infaq” (charitable giving), met many needs of the community. One of the Islamic states where the waqfs are very active was the Ottoman Empire. The range of waqf services in the Ottomans expanded so much that, besides serving individuals and community, waqfs for injured birds and sick animals were also established. The fact that the waqfs are so widespread in the state has made it possible to refer the Ottoman Empire as a waqf civilization. One of the waqf types operating in the Ottoman Empire was the cash waqfs (CWs) which hold cash money as capital. The CWs operated its capital with various Islamic finance methods. Revenues obtai­ned from various investments were used for the purpose of waqf. The CWs met the vital necessities of the society pertaining to education and religion in the period they were active in the Ottoman Empire. Another function of these waqfs was to operate as a micro-credit mechanism. Through these waqfs, the surplus and the accumulated savings in the hands of the wealthy people were made available to merc­hants, farmers, craftsmen, and artisans. Hence, these waqfs have served as resource transfer channels as well as functioning as a charity in the society. The main goal of CWs, which is the pioneer of modern Islamic financial institutions, is different from that of Islamic interest-free financial institutions. The CWs did not transfer the profits they obta­ined to the waqf’s founder or owner. The income obtained was spent to fulfill the charitable services. Therefore, these institutions created an altruistic finance model operating within the borders of Islamic rules and orders. Therefore, this model has its own principles. In our study, the financial mentality of the Ottoman society in the context of CWs and how this mentality shaped them will be discussed. The basic principles of this mentality and CW model will be emphasized.