Introduction: A parastomal hernia (PSH) is an abnormal herniation of an intra-abdominal organ or other tissue through an intentionally created fascial defect at an ostomy site. PSHs commonly involve reducible mobile segments of omentum, intra-abdominal fat, and bowel. However, PSHs may rarely involve fixed intra-abdominal organs such as the stomach. Case Description: A 68-year-old female underwent emergent Hartmann procedure for Hinchey III diverticulitis and subsequently developed a large reducible parastomal hernia. She was scheduled for an elective laparoscopic colostomy reversal. Prior to her scheduled reversal, the patient presented to the ED with anorexia, lack of colostomy output, emesis, and pain localized to her left lower quadrant. She was found to have gastric outlet obstruction secondary to herniation of the stomach through the left lower quadrant colostomy site. The patient was admitted and treated conservatively with resolution of her symptoms, but due to the high likelihood of recurrence, the decision was made to proceed with laparoscopic Hartmann colostomy reversal with coloproctostomy and primary closure of the fascia without mesh. Conclusion: The contents of a PSH can become incarcerated causing obstruction, strangulation, necrosis and even perforation over time. Fortunately, in this case, herniation of the stomach was recognized early. The patient underwent repair of the hernia defect in order to prevent recurrence of gastric herniation and its potential detrimental complications. The decision regarding the technical aspects of ostomy reversal in terms of mesh selection require further study. In our case, mesh was not used due to patient-specific factors and comorbidities.