© Trakya University Faculty of Medicine.Background: Desmoid tumors are uncommon and benign mesenchymal neoplasms. The optimal treatment of patients with desmoid tumors is still controversial. Surgery is the primary treatment for locally invasive or recurrent desmoid tumors. Also, radiotherapy is a treatment option for patients at high risk for local failure such as those with positive margins or recurrent and unresectable tumors. Aims: To report our institutional experience and longterm results of patients with desmoid tumors who received radiotherapy. Study Design: Retrospective cross-sectional study. Methods: Between 1980 and 2009, 20 patients who received radiotherapy (RT) in our institution were analyzed. The majority of patients (80%) were referred with a recurrent tumor after previous surgery. Thirteen patients underwent marginal resection, 4 had wide local excision and 3 patients had only biopsy. Resection margin was positive in 15 (75%) patients. All patients received radiation therapy. The median prescribed dose was 60 Gy. Five patients received less than 54 Gy. Results: The median follow-up time was 77.5 months (28-283 months). Nine patients developed local recurrence after RT. Seven local failures (78%) were in field. Time to local recurrence ranged from 3-165 months (median 33 months). The 2-5 year local control (LC) rates were 80% and 69%, respectively. On univariate analysis, the 5 year local control rate was significantly better in the patients treated with ≥54 Gy than in patients who received <54 Gy (p=0.023). The most common acute side effect was grade 1-2 skin toxicity. As a late side effect of radiotherapy, soft tissue fibrosis was detected in 10 patients and lymphangitis was seen in 1 patient. One patient developed radiation-induced sarcoma. Conclusion: According to our results, radiotherapy is especially effective in recurrent disease and provides a high local control rate in the patients received more than 54 Gy.