It was believed that the main obstacle for the development of under developed countries is the lack of capital, and therefore, they are trapped in the vicious circle of under development and except for injecting capital from abroad, they have no other way out from this vicious circle.But today this view is quite changed, and also capital is the necessary condition for development; it is not the sufficient condition; because those developing countries which have many natural resources and God given wealth and adequate capital, have proven that they can develop even with a limited amount of capital. One of the suitable methods for achieving development is to use efficient financial systems to mobilize the small-but numerous- idle capital available across the country, because these efficient financial systems can mobilize private' savings and allocate them to productive investments through their own systems, while facilitating the transaction of goods and services, will reduce the risk and capital expenses, and at last, by compiling capital and technical innovation, create job opportunity and increase income capacities.The Micro Financial Institutions as a part of monetary and credit system of the country can play an important role in this regard. They can play a complimentary role in mobilization of financial resources, specially the idle money resources available in rural area, and the allocation of these funds (the Grameen Bank of Bangladesh is a good example of this method). Therefore, the settling down these institutions has a very high priority in development plans of monetary sector of the country. In this study, by reviewing the performance and successful experiences of Grameen Bank of Bangladesh and interest-free funds (gharz al hasana) in Iran and comparing their degree of influence, financial self-sufficiency, the ratio of deposits to loans, value added to given credits, and value added to the number of staff, I try to find suitable solutions for the problems facing Micro Finance in our rural sector of the country. Thus, the purpose of this study is the understanding the cost-benefit of these two applied models of Micro Finance, and introducing an applicable model for our country. The study shows that the influence indicator, self sufficiency and the ratio of value added to credits of interest-free funds of rural areas in Iran are very smaller than those of Grameen Bank of Bangladesh.