In an outsourcing relation both parties have an obligation to provide knowledge and a need for receiving knowledge. Whether or not this KM is successfully contributing to the outsourcing business is therefore depending on both parties, but to create a win-win situation the knowledge sharing is necessary. Based on this background knowledge, practical quantitative and qualitative research was done in this management research. Using interviews, twelve experts who have participated in outsourcing agreements from one perspective or another, were questioned about the CSF of KM in outsourcing by analysing the importance and fulfillment of strategic, cultural, organisational and technological aspects. From this, critical influencing factors and challenges were identified using a portfolio analysis framework. This portfolio approach along with specific strategic recommendation hands companies wishing to optimise their outsourcing activities a feasible strategic instrument. In addition, the findings of this book provide each single company valuable orientation to determine the levels of importance and fulfillment for each success factor on their own.