We report the case of a 22-year-old-man having a familial adenomatous polyposis coli treated by total colectomy with ileo-rectal anastomosis. Two years after the operation, an asymptomatic mesenteric fibromatosis appeared which was nonresectable due to mesenteric vessels infiltration. Nine years later, sulindac therapy was started for residual polyps in the rectal stump. This treatment was taken intermittently, during periods of 1 to 8 months, for 6 years. After 4 years of treatment, the tumor was no longer palpable. Four years after sulindac discontinuation, the patient was operated on for suspicion of intestinal adhesion. The mesenteric fibromatosis had completely disappeared and mesenteric vessels were free. This complete macroscopic regression of a desmoid tumor after sulindac therapy emphasizes again the interest of this treatment for mesenteric fibromatosis.