Background: Patients are often not told about harmful medical errors. The malpractice environment is considered a major determinant of physicians' willingness to disclose errors to patients. Yet, little is known about the malpractice environment's actual effect on physicians' error disclosure attitudes and experiences. Methods: Mailed survey of 2637 physicians (62.9% response rate) in the United States (Missouri and Washington) and Canada, countries with different malpractice environments. Results: Physicians' error disclosure attitudes and experiences were similar across country and specialty. Of the physicians, 64% agreed that errors are a serious problem. However, 50% disagreed that errors are usually caused by system failures. Ninety-eight percent endorsed disclosing serious errors to patients and 78% supported disclosing minor errors; 74% thought disclosing a serious error would be very difficult. Fifty-eight percent had disclosed a serious error to a patient, and 85% were satisfied with the disclosure, and 66% agreed that disclosing a serious error reduces malpractice risk. Respondents' estimates of the probability of lawsuits were not associated with their support for disclosure. The belief that disclosure makes patients less likely to sue (odds ratio, 1.58), not being in private practice (odds ratio, 1.47), being Canadian (odds ratio, 1.43), and being a surgeon (odds ratio, 1.26) were independently associated with higher support for disclosing serious errors. Conclusions: US and Canadian physicians' error disclosure attitudes and experiences are similar despite different malpractice environments, and reveal mixed feelings about disclosing errors to patients. The medical profession should address the barriers to transparency within the culture of medical and surgical specialties.