Physician disclosure of medical errors to institutions, patients and colleagues is important for patient safety, patient care and professional education, yet numerous factors pose impediments to disclosure. The authors of this article saw a need to define and organize the various influences on error disclosure in order to enhance interventions and to aid in the interpretation of the results of interventions. They reviewed 316 articles dealing with the physician experience of error reporting and identified 91 factors. Twenty-seven further factors were derived from exploratory focus group transcripts. Then quantitative analysis was used to organize the factors and confirmatory focus groups, and expert review validated the results. This sequence of methodologies helped the authors to develop a taxonomy of factors impeding disclosure (attitudinal barriers, uncertainties, helplessness, fears and anxieties) and facilitating factors (responsibility to patient, responsibility to self, responsibility to profession, responsibility to community). The taxonomy can serve to guide the design of error-reporting systems and to inform educational interventions to promote the disclosure of errors to patients. Future research will need to ascertain whether educational and institutional interventions actually reduce the influence of impeding factors or enhance the influence of facilitating factors.