The international community has made a strong commitment to the Millennium Development Goals (MDGs). Many donor agencies want to know whether microfinance, or financial services for the poor, is an effective tool for reaching the MDGs. In response, CGAP launched a study of the empirical evidence on the poor’s access to financial services and how this access supports the MDGs. This brief summarizes the results of recent professional studies on the impact microfinance, recognizing the difficulties of comparing studies that apply different levels if methodological rigor.