The case of a giant sigmoid diverticulum complicated by a volvulus of the bowel is reported. After an exhaustive literature review, the Authors analyse the aetiopathogenetic, physiopathological and clinical aspects of this rare condition, considering its diagnostic and therapeutic implications. The Authors describe surgical problems and therapeutic management, pointing out that without an accurate study by radiological imaging, it is very difficult to diagnose the condition, particularly when no specific symptoms have been observed.