Adverse events after hospital discharge are a known patient safety hazard, but similar events between ambulatory clinic visits are poorly described. This study longitudinally followed a vulnerable patient population with diabetes between clinic visits and discovered 86% experienced at least one adverse or potential adverse event during the 9-month observation period. Medication management was the most common domain identified, while 80% of all events had a combination of system, clinician, and patient factors contributing. The authors discuss the complex safety environment observed and highlight that patients themselves may be key vehicles for reducing events. A past AHRQ WebM&M interview discusses the challenges in safely caring for vulnerable patient populations in the ambulatory setting.