Spontaneous perforated Meckel's diverticulum is a rare complication and mimics appendicitis or diverticulitis in elderly adults. We report the case of a 51-year-old man who presented to the emergency department with abdominal pain that had progressively increased over the previous two hours. The provisional diagnosis was appendicitis or diverticulitis, and we recommended computed tomography for further evaluation. Computed tomography of the abdomen showed an outpouching, blind-ending, fluidfilled structure in continuity with the distal ileum that depicted wall perforation and extraluminal air bubbles, consistent with perforated Meckel's diverticulum. In this case report, computed tomography provided a clear imaging diagnosis of perforated Meckel's diverticulum preoperatively. Thus, in patients with acute abdomen, complicated Meckel's diverticulum should be included in the differential diagnosis.