This commentary discusses the role organizations play in producing and contributing to medical errors. The authors contrast characteristics of error-prone organizations with high-performing ones and provide specific illustrations of how each type of organization designs and executes work, responds to problems, and reacts to the consequences. Examples from health care settings are included as well as discussion of case studies previously published in the Annals’ "Quality Grand Rounds" series. The authors suggest that health care organizations should not strive to become factories of repetition but, rather, should aim to define specific processes to foster an environment of continuous learning and improvement.