Medical confidentiality is a core concept of professionalism and should be an integral part of pregraduate and postgraduate medical education. The aim of our study was to define the factors influencing attitudes towards patient confidentiality in everyday situations in order to define the need for offering further education to various subgroups of physicians. All internists and general practitioners who were registered members of the association of physicians in Geneva or who were working in the department of internal medicine or in the medical polyclinic of the University Hospital of Geneva in 2004 received a standardised questionnaire. Physicians were asked to indicate for seven vignettes whether a violation of confidentiality had occurred and whether the violation was not important, important or serious (scores 1-3; no violation = 0). 508 completed questionnaires were returned (participation rate 55%). Physicians who had worked in the hospital for more than 20 years identified violations of confidentiality more often than physicians with less hospital experience. Binary logistic regression showed that ethics education, total years of professional experience, being an internist, having a private practice, the length of working in private practice and gender were factors associated with correct identification of violations and their severity. However, each factor played a specific role only for single cases or a small number of situations (Cronbach alpha <0.6). Postgraduate education programs on confidentiality should be offered to a wide range of physicians and should address specific hypothetical situations in which there is a risk of avoidable breaches of confidentiality.