Checklists have proven to be a remarkably powerful patient safety intervention. A vivid demonstration of the power of checklists came in a landmark World Health Organization study of a safe surgery checklist, which achieved significant reductions in mortality and complication rates in a global population. One criticism of checklists is that in urgent situations, pausing to ensure checklist completion could be harmful. However, this subgroup analysis of the original WHO study found that the surgical safety checklist successfully reduced mortality and complications in patients undergoing urgent surgery (defined as operation within 24 hours of assessment). This study also demonstrates the feasibility of implementing standardized safety interventions in hospitals with widely differing resources and patient populations.