BACKGROUND: Physicians should be able to distinguish situations where they need to protect confidentiality from those where they could be obligated to reveal information. Data are scarce concerning physician's attitudes in daily situations where violations of confidentiality are avoidable. Physicians should be aware of situations where patients are identifiable. AIM: To solicit participation of primary care physicians in a teaching intervention and to explore participants' opinions on violations of confidentiality. DESIGN OF STUDY: A questionnaire presented seven vignettes describing avoidable violations of confidentiality (for example, without patient consent a physician mentions a politician's illness their spouse). Participants answered on a scale of 0-3 (0=no violation and 3=serious violation). All contacted physicians were invited to a teaching session during which the study results were discussed. METHOD: Three-hundred and seventy-eight members of the Association of Physicians in Geneva (community physicians) working in primary care medicine, and 130 GPs and internists working at the University Hospital of Geneva (hospital physicians) took part. Physicians' answers were compared to responses from Swiss, UK, and other European law professors, and from 311 medical and law students in Geneva. RESULTS: Between 4% (case 6) and 57% (case 2), of physicians thought that no violation occurred. Law professors attributed the scores to each case as 3, 3, 2, 3, 2, 3, 3; the means of physicians were: 1.9, 1.4, 0.7, 1.4 (hospital physicians)/1.9 (community physicians), 0.4, 1.6, 2.6. In most cases, physicians' and students' answers were similar. A significantly higher percentage of community physicians than hospital physicians and students thought that a physician violates confidentiality if they provide the list of their patients to the police for the investigation of the theft of a purse in the waiting room. CONCLUSION: Physicians need to be fully aware of their obligations towards patient confidentiality. Avoidable breaches of confidentiality occur when colleagues and authorities (such as police and those in a judicial context) ask for information.