Micro-finance Institutions (MFI) is an organization that provides financial services (microcredit, saving schemes, etc.) to the poor who are considered as not bankable . MFIs have been proven as a great contributor in poverty alleviation in addition to bringing development to the poorest areas in the world which in the long run will reduce world poverty; however their sustainability is at stake. It is vital to understand the variables that impact the failure and success which determine its sustainability. Hence, we aimed to answer this research question How MFI s reinvent their business model in order to stay sustainable. This book focuses on Business Process Re-engineering as one of the tools to make MFIs sustainable in the long run. A case study analysis on Grameen Bank s transformation into Grameen II was taken consecutively to analyze how a MFI carries out a business reengineering process. The aim of this book is to show MFI s on how they can survive for long periods and be successful as well.