IMPORTANCE The Hartmann procedure (end colostomy) remains a common operation for diverticulitis requiring surgery. However, the timing of subsequent colostomy reversal remains widely varied, and the optimal timing remains unknown. OBJECTIVE To investigate the association of the timing of colostomy reversal with operative outcomes. DESIGN, SETTING, AND PARTICIPANTS This retrospective analysis of the Healthcare Cost and Utilization Project State Inpatient Databases for California, Florida and Maryland included patients with colostomy for diverticulitis linked to their colostomy reversal. Patients with readmissions between the index surgery and reversal were excluded, leaving a final cohort