['Optimal timing of surgery for acute diverticulitis remains unclear. A non-operative approach followed by elective surgery 6-week post-resolution is favored. However, a subset of patients fail on the non-operative management during index admission. Here, we examine patients requiring emergent operation to evaluate the effect of surgical delay on patient outcomes.', 'Patients undergoing emergent operative intervention for acute diverticulitis were queried using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2005 to 2012. Primary endpoints of 30-day overall morbidity and mortality were evaluated via univariate and multivariate analysis.', 'Of the 2,119 patients identified for study inclusion, 57.2\xa0% (n\xa0=\xa01212) underwent emergent operative intervention within 24\xa0h, 26.3\xa0% (n\xa0=\xa0558) between days 1-3, 12.9\xa0% (n\xa0=\xa0273) between days 3-7, and 3.6\xa0% (n\xa0=\xa076) greater than 7\xa0days from admission. End colostomy was performed in 77.4\xa0% (n\xa0=\xa01,640) of cases. Unadjusted age and presence of major comorbidities increased with operative delay. Further, unadjusted 30-day overall morbidity, mortality, septic complications, and post-operative length of stay increased significantly with operative delay. On multivariate analysis, operative delay was not associated with increased 30-day mortality but was associated with increased 30-day overall morbidity.'] Is post-operative morbidity , but not mortality , worsened by operative delay in septic diverticulitis?