Prior research has shown that patients are concerned about medical errors and desire full disclosure of errors when they occur. However, patients' perceptions of what constitutes an error may differ from health care providers' perceptions. This study surveyed more than 1600 patients recently discharged from 12 hospitals to determine what patients considered to be an error and to evaluate patients' perception of their safety during their recent hospitalization. Patients defined "error" more broadly than traditional definitions, including such issues as falls, communication problems, and perceived lack of attentiveness by providers. Although nearly all patients felt safe overall, 39% experienced at least one error-related concern during their hospitalization, most commonly due to well-recognized problems such as medication errors. The authors recommend incorporating such patient views into patient-centered safety programs.