BACKGROUND: The purpose of our study was to compare the characteristics of medical practitioners who prefer using the Internet as their information resource and those who prefer using printed materials.<BR>METHODS: From December 2002 to January 2003, a non-anonymous questionnaire was sent out by post to members of the Japanese Medical Association (JMA) and physicians working in hospitals. Contributing factors were examined by using logistic regression analysis.<BR>RESULTS: The response rates for the questionnaires were 18.7% (n=1868) for JMA physicians and 68.0% (n=5901) for hospital physicians. Factors associated with the preference for using the Internet were: 'younger age'; 'use of the Internet to solve clinical problems and uncertainties'; 'use of personal computers at work'; and, 'use of personal computers at home'.<BR>CONCLUSION: The results of this study show that, although some younger physicians prefer printed materials, providing medical information via the Internet is better suited for younger physicians who are making full use of computers. In contrast, older physicians prefer printed materials because they tend to be less familiar with using computers and may have limited accessibility to the Internet. Therefore, using both the Internet and printed materials to provide medical information is necessary to meet the needs of the larger physician population.