Knowledge management (KM) attracts more and more attention nowadays in either research or practice. Organisations often spend a lot of time and money to launch strategic KM initiatives without first assessing whether or not their culture is ready for the implementation of such initiatives. If the culture is not ready for implementing the initiatives, the effort put will rarely produce significant long-term benefits. Instead, employees will perceive them as a waste of time, and participate less actively in the KM initiatives. In this paper, a KM culture assessment tool (KMCAT) is purposely developed for assessing the organisational culture so as to ensure the success of implementation of KM initiatives. The KMCAT takes into account coherence, control, alliance and partnership, information and communication technology as well as innovation, which help an organisation to reveal culture profiles and hence provide directions for managing the culture. A case study of applying the KMCAT is undertaken in an aviation company and encouraging results are obtained.