An intra-abdominal desmoid tumour included in Gardner's syndrome is described. Some aspects of this unusual tumour are reviewed, emphasizing the value of CT to evaluate shape, location, size and relation with adjacent structures and therefore to decide the therapeutic plan, to avoid the need for exploratory laparotomies which are, moreover, so inadvisable in these patients. Although the, treatment of choice is surgery, it must be performed in accordance with CT findings. When surgery is not possible is incomplete or after recurrences, alternative methods are recommended.