The sigmoid colon is the most frequent site for a volvulus due to anatomical and pathological reasons. When the rotation of the loop occurs slowly, the sigma can greatly blow up and stretch. We report the clinical case of an 80-year-old woman admitted to our Department for an enormous volvulus of sigmoid colon. Physical examination, abdominal X-ray and CT-scan were performed to diagnose the disease. At the surgical procedure the sigma was about 50 centimetres in length and 15 centimetres in diameter, with a gangrenous necrosis of the loop; the treatment was a sigmoidectomy by Hartmann procedure. Surgical resection is the only therapeutical option for volvulus in advanced stage due to a late diagnosis.