Clinicians frequently do not fully disclose errors to patients; lack of training in disclosure practices and fear of malpractice lawsuits are often cited as reasons why clinicians avoid disclosure. This study investigated the role of physicians' personal morality in attitudes toward error disclosure. Internal medicine residents were asked to complete a validated test of ethical reasoning and then to describe how they would disclose an adverse drug event experienced by one of their patients. Although hampered by a low response rate, the study did find that residents with higher ethical reasoning scores were more likely to fully disclose the error, apologize for the error, and acknowledge personal responsibility. In addition to training on disclosure methods, this study implies that ethical training may improve the quality of error disclosure.