A 61-year-old man attended an outpatient colorectal clinic for a chronic, non-specific abdominal pain, associated with rectal bleeding. He underwent a number of investigations including a CT pneumocolon, which revealed an incidental finding of 20 cm of additional sigmoid colon. This case is interesting because tubular sigmoid duplication is an extremely unusual condition, rarely diagnosed in adults; only a few cases have been reported of this condition in the adult population. Our team chose to treat this patient conservatively, in order to avoid putting the patient at risk of an unnecessary surgery.