Project complexity keeps rising as businesses expand in size and scope. In order to better manage the portfolio, firms have responded by implementing the PMO: an office which aims to supervise each project. Depending on the requirements, the nature and the maturity of the organization that establishes the PMO, the physical and material installation varies, but a generic and common process could be defined. This master thesis focuses on explaining the implementation of the PMO in a real-world example, in this case the organization where the candidate completed the internship, as well as the transformation and adaption of the PMO as a response of internal and external company challenges, during the effective deployment.