In recent literature, mucoceles have been discovered to be in the appendix vermiformis or in the nasal sinuses. Although rare, colonic mucoceles, as well as rectal mucoceles, have also been encountered. Furthermore, colonic mucoceles arising from a diverticulum is an even more unusual occurrence, and to date, there has been only one reported case. We present a 48-year-old male with a past medical history of multiple episodes of diverticulitis who presented to the emergency department complaining of bilateral lower quadrant abdominal pain for three days. Upon arrival to the emergency department, the patient had a CT scan of the abdomen and pelvis, which showed an annular constricting 65 mm mass in the proximal sigmoid causing large bowel obstruction. The patient underwent unsuccessful endoscopies and inevitably underwent a hand-assisted laparoscopic sigmoid resection. The following days, the biopsy returned and resulted to be a mucocele arising from a sigmoid diverticulum. We encountered the very first benign colonic mucocele arising from a sigmoid diverticulum.Copyright © 2020, Alcantar et al.