Colocolic intussusception in the adult, caused by a tumoral process, is a rare clinical event. We have studied two adults clinically presenting with a mass in the right iliac fossa, which was produced in one case by a carcinoma involving the right colon and in the other case involving the sigmoid. Multi-slice spiral CT imaging showed the presence of a colocolic intussusception-the tumoral characteristics of the lesion eliminated the possibility of a lipoma-and it allowed a satisfactory presurgical evaluation of the pathological process.