Purpose <p>Sigmoid resection with end colostomy (Hartmann’s procedure) is the procedure of choice when a large bowel obstruction secondary to diverticular disease requires surgery. Less morbid alternatives are less common. This study compares a transverse blowhole colostomy as a first-stage intervention in diverticular-associated obstruction. Our primary aim was to compare colostomy reversal rates and postoperative outcomes between blowhole colostomy and Hartmann’s procedure.</p> Methods <p>This is a single-center, retrospective cohort study. An institutional database was utilized to retrospectively identify adult patients who underwent Hartmann’s procedure or blowhole colostomy for diverticular strictures with obstruction between 2012 and 2023.</p> Results <p>Thirty-nine patients underwent Hartmann’s procedure for diverticular strictures with obstruction and 15 patients underwent blowhole colostomy. The blowhole colostomy group had a significantly shorter postoperative length of stay (median 5 vs. 8&#xa0;days, <i>p</i> = 0.01). Colostomy reversal was more frequent in the blowhole group (81.3% vs. 56.4%, <i>p</i> = 0.08), with a shorter median time to reversal (3&#xa0;months vs. 4.7&#xa0;months, <i>p</i> = 0.01). A significant increase in reversals performed using a minimally invasive approach (84.6% vs. 50%, <i>p</i> &lt; 0.01) occurred in the blowhole colostomy group. No significant differences were observed in other postoperative outcomes, including proximal diversion after colostomy reversal.</p> Conclusions <p>Blowhole colostomy may be a viable alternative to a Hartmann’s procedure for diverticular-associated large bowel obstruction, offering potential benefits such as shorter hospital stays, higher rates of colostomy reversal, and a greater likelihood of minimally invasive reversal. Further prospective studies are needed to confirm these findings.</p>