Problem Based Learning (PBL) has been fully or partly adopted by several medical and dental schools throughout the world, but only few attempts have been made to adjust this method to Distance Learning (DL) environments. It appears that the interaction demands of PBL could not be easily facilitated by the technologies used for DL in the past. The recent introduction of Virtual Learning Environments or Virtual Classrooms, is suggested by many as the development that could allow Distance Learning to utilise highly structured collaborative learning methods such as PBL. A literature review and two pilot studies were undertaken, in an attempt to investigate the possibility of adjusting an existing in-classroom PBL model to Internet-based environments for distance learning. There is a strong need of a conceptual theoretical framework and research results to support the function and effectiveness of distance learning in health education. Drop-out rates are still high in all kinds of distance education. Accreditation, team-work and personal contact, appear to be factors of importance for increasing motivation and minimising drop-out rates in distance learning. During the pilot studies it was evident that both postgraduate and undergraduate students were very positive towards the PBL method, as they experienced it while working over the network. However, it is very difficult to introduce inexperienced students to PBL through distance. Students? competence with computers seems to be an important factor for the success of a virtual classroom and their computer literacy has to be objectively assessed prior to any course. Significant differences were identified between in-classroom and over the Internet communication. These differences, although measured in the quantity of interaction, appear to influence the quality and depth of discussion as well. Tutor involvement was higher in the Internet discussions than the in-classroom ones. It was concluded that an entirely Internet-based PBL course is possible, if properly organised. However, such a model might constitute a compromise over the quality standards of in-classroom PBL, at least with the currently available Internet technology. A hybrid approach, which will combine personal contact with network-based interaction, might be the safest and most beneficial option right now.