Although traditionally the majority of patient safety efforts have focused on inpatient care, the overwhelming bulk of health care actually takes place in the ambulatory setting. Accordingly, the scope of widespread documented adverse events among outpatients is vast. Updating a previous report, this publication analyzes efforts to improve patient safety in ambulatory care over the past decade and identifies gaps that future research should address. Dr. Richard Baron discusses patient safety in the office setting in an AHRQ WebM&M perspective.