The main focus of this research is to critically evaluate the sustainability issues of Interest-free Micro–Finance Institutions (MFIs) in general and a recently developed micro finance model - Rural Development Scheme (RDS) of Islamic Bank Bangladesh Limited (IBBL) in particular. Recently, in micro finance literature, the term sustainability or self-sustainability” has been discussed and analyzed widely among the practitioners, researchers and policy makers as an important development indicator of both MFIs and its clients. It is well known that only efficient institutions can low the high cost of servicing small and irregular incomes on a sustainable basis. These lower costs can in turn be passed on to the poor/hardcore poor in the form of low finance charges, which leads to contribute their smooth income generating activities. In this context, the present study is an endeavor by the researcher to examine mainly the institutional, financial and economical sustainability of the above model by using various indicators. The empirical analysis of the study reveals that RDS of IBBL has been treated as a sustainable MFI in the rural development and poverty alleviation of Bangladesh with a short span of time of its establishment. Finally, the study also suggests some policy guidelines for the smooth functioning and development of the afreosaid interest –free MFI in any region like Bangladesh.