When the world is fighting against poverty and hunger, a new concept has emerged in the last couples of decades as Microfinance that prove loan to marginal and underprivileged people. Considering the nature and field of operation including increasing requirements, the outreach and sustainability have become prominent success factor for microfinance institutions. Outreach and sustainability indicate wide range of services and long term existence not only in quantity but also in quality improvement. This study deployed Sustainability Dependency Index (SDI), Sustainability Dependency Ratio (SDR) and Efficiency and Subsidy Intensity Index (ESII) techniques to measure the sustainability of Buro (Bangladesh Unemployed Rehabilitation Organization), a prominent microfinance institution of Bangladesh. From the analysis, Buro has been found to progress towards achieving outreach and sustainability from 2001 to 2005, and then this trend deteriorates in 2006 and 2007. The study reveals that microfinance institutions should concentrate on enhancing financial efficiency and reducing reliance on subsidies. As the urge for micro credit is increasing day by day, microfinance institutions still have lots of opportunities to put more emphasize on outreach and sustainability factors. This study on Buro shows ongoing trend and connotations for overall microfinance market in Bangladesh.