In the article titled “Association of β-Blocker Therapy With Risks of Adverse Cardiovascular Events and Deaths in Patients With Ischemic Heart Disease Undergoing Noncardiac Surgery: A Danish Nationwide Cohort Study,” published online November 18, 2013, and also in the March 2014 issue of JAMA Internal Medicine (2014;174[3]:336-344. doi:10.1001/jamainternmed.2013.11349), an error ocurred in one part of the composite major cardiovascular adverse events (MACE) end point. All analyses were recalculated after correction of the end point, and the values were substantially unaltered. More important, none of the study’s conclusions were affected. This article was corrected online.