For the past few years, Agile methodologies have been hailed as the silver bullet which will successfully address the high project failure rate. Many organisations have been using a traditional project management methodology for years and are now either considering or in the progress of introducing a more agile approach as a substitute for the more rigid, inflexible and control oriented traditional methodologies. Potential benefits include, but are not limited to, faster return on investment, better products/services, and higher customer satisfaction. Often however, this leads to a painful introduction because employees are uncomfortable with the drastic changes Agile methods impose or because there is internal resistance to change, and in many cases the expected increase in project efficiency does not occur. The purpose of this thesis was to determine the perceived challenges related to organisational adaptation to agile project management and to develop a conceptual model of best practices to help guide agile adaptation. Research and data collection was performed through a review of relevant literature within both traditional and agile methods, principles and techniques, along with papers on organisational transformation and case studies and in parallel, interviews with experts and practitioners in the field. Data analysis was performed in two phases: the literature review helped us find data in relevant project management fields and through a subset of the Burke-Litwin organisational change model extract challenges and questions, and in the second phase the outcome of interviews based on these questions was fed back through the change model, analysed and compared with the original data. Some of the main findings of this thesis are: - Adaptation to an environment with less structure and control is often a hard challenge, but it can be overcome with proper guidance and the support of a high-level internal sponsor who champions the agile vision top down. - The change in management style from the traditional „command and control‟ to self-regulation is a challenge for former project managers, who must evolve into project facilitators. - For agile adaptation to be successful, it should be implemented company-wide, and not in for instance a single department.