The microfinance sector has already proven its capacity to reach populations excluded from formal financial services through innovations in products and delivery systems. However, rural microfinance raises further challenges. If they are to be effective, rural microfinance services must develop beyond the current standard, one-size fits all microfinance model The challenge for rural microfinance institutions is to adapt to the diversity and complexity of the rural demand for financial services, in order to comply with their social mission and to promote virtuous circles of rural development, while sustaining internal balances and financial as well as organizational viability. This challenge first raises the issue of the social mission and accountability of microfinance institutions, which fits into the broader concept of social responsibility. It also raises the issues of their technical, financial and organizational capacity to innovate, to react to clients feedback, to adapt to changing and often adverse environments etc.