Presentation We describe an unusual presentation of sigmoid colon perforation secondary to an ingested chicken bone. Diagnosis The patient presented with a 4 day history of abdominal pain and distension. On examination there were signs of peritonism. Inflammatory markers were raised. Computed tomography revealed a linear density projecting through the wall of the colon. Treatment The patient underwent emergency laparotomy and a Hartmann's procedure. A chicken bone was found to be the causative foreign object. Conclusion Foreign body ingestion is an uncommon cause of sigmoid perforation which may mimic more common surgical presentations such as diverticulitis.