PURPOSE: Keloid is a clinical term characterized by elevation and extension of scar tissue beyond wound margin. Currently, there is no known treatment that shows consistent effect in all patients. Postoperative radiation therapy is known to prevent recurrence of keloid. METHODS: We reviewed data of patients who had undergone operation or operation followed by radiation therapy at our institute for the last 12 years. Follow up was possible in 39 patients(21 patients treated only by operation and 18 treated by operation and radiation therapy) We then investigated recurrence in both groups by VAS score. By mail, patients were asked to score their current condition on the bar in 4 aspects(itching, pain, mass lesion(by patients and other persons)). Two criteria were used for defining successful treatment. One is the case which total VAS score was 0, and the other is sum of VAS score of mass lesion was 0 to 5. RESULTS: In the former, recurrence rate is 90.5% in operations-only group but 66.7% in operations plus radiation therapy group(p 0.05). In the latter, recurrence rate is 66.7% in operation-only group but 22.2% in operations plus radiation therapy group(p 0.05). CONCLUSION: These results shows postoperative radiation therapy is effective method in keloid treatment.