Microfinance institutions provide financial services to the poor who are excluded from service by classical banks. In Rwanda, despite of a set back in the year 2006, they have proven to be important players in the economic development through participating in poverty alleviation by providing financial services to the poor class. This research was designed to analyze the success factors in selected institutions in Rwanda. Focus was on analyzing characteristics, services and loan management, strategies and planning, and product design. Furthermore, client characteristics,their feedback evaluation of the institutions in addition to success factors and challenges were studied. Questionnaires were distributed to both managers and clients after using a focus group to validate the questionnaires. It was found that although the institutions have been growing and performing successfully through changing business and life style of their clients, they need to think ahead and plan to develop more products and services to match clients needs. Otherwise, their success may be risked by the stiff competition currently existing in the financial market in Rwanda.