Desmoid tumours present difficult management problems in patients with Gardner's syndrome. We recently studied two patients with Gardner's syndrome, who developed a desmoid tumour arising of the abdominal wall and mesenteric root. One patient had a total resection of the mesenteric desmoid tumour followed by postoperative radiotherapy. No recurrence occurred in the last three years. The other patient had an incomplete resection and refused postoperative radiotherapy. Abdominal CT scan revealed tumour expansion 6 months postoperatively. From our experience and with respect to current literature, we suggest that complete surgical excision combined with radiotherapy (4.000-6.000 rads) could diminish the recurrence rate of desmoid tumours. When resection is incomplete or technically impossible, radiotherapy remains the second choice of treatment.