This paper discusses barriers which arise during the change process from a traditional educational system to a problem-based educational model. The characteristics of a problem-based learning model are presented in order to provide a framework for discussion of the scope of these issues. Then the findings of a research study, which examined an actual transition from a traditional model to a problem-based learning model, are introduced and discussed. In spite of an extensive staff development programme to introduce teachers to the new model, some unforseen issues arose. Some of these were to do with the nature of teaching in the new model, for example, the requirements of project supervision as the new form of teaching, which was quickly brought into focus by teachers involved in the transition. Other issues were to do with the retention, in this particular example of problem-based learning, of forms of teaching which appeared similar to traditional teaching, namely lectures. The findings suggested that it was very important to 'rethink' known teaching methods such as traditional lecturing, because teachers have to reselect the content of courses if the number of lectures is substantially reduced. Furthermore, the results of the study indicate that the importance of the change processes at the educational model level focus on the individual, culture and the organization. For faculty and academic developers this means that they have to facilitate all three levels which is a comprehensive challenge and requires a high level of competency.