Preventing medication errors remains a focus of safety interventions, particularly for high-risk medications such as insulin. While insulin-related adverse events are well described in hospital and nursing home settings, the scope of the problem in ambulatory care is less understood. This study analyzed nearly 4000 insulin exposures reported to poison centers over the past decade and found a mean annual increase of 18% over that time period. Unintentional therapeutic errors accounted for 68% of the total with a progression from 41% to 78% over the study period. Factors associated with these errors included adults older than 40 years and administration in the late evening hours. These findings raise opportunities for improvement in insulin safety outside the heavily studied inpatient setting. A past AHRQ WebM&M commentary discussed the challenges in managing insulin therapy in the hospital setting.