The experience of 66 cases of colovesical fistula is reported. The most common cause was diverticular disease (71%), the remainder being due to malignancy, Crohn's disease, radiotherapy, appendicitis and trauma. The most sensitive investigation was barium enema, which was abnormal in 98% and actually showed the fistula in 57%. In 32 patients a single stage resection was performed, without mortality or significant morbidity and we would advocate this form of treatment for fistulae which are not complicated by gross sepsis or obstruction.