We retrospectively evaluated our therapetic results in ductal carcinoma in situ (DCIS) patients treated with postoperative radiotherapy following breast-conserving surgery (BCS). Sixty-seven DCIS patients were treated with curative radiotherapy (RT) after BCS, in our department from December 1998 to January 2008. All patients have been treated with 6 MV photon energy on lineer accelerator machine. Radiotherapy treatment fields were opposed tangential to the whole breast. A total dose of median 50 Gy (48-50 Gy) was delivered in five fractions in a week. In twenty patients, boost dose to the tumour region was applied. Fifty patients received systemic hormonotherapy. Median follow-up time was 44 moths (range 12-122 months). Five-year OS, DFS and local control rates were found as 96%, 97% and 97%, respectively. There was only one ipsilateral breast recurrence in our study (2%). Two patients died due to other causes except disease (3%). Grade III dermatitis was seen in only one patient (2%), and there was no serious acute side effects in 41 patients (63%). There was no late side effect in our patients. Sixty-two patients were alive without evidence of tumour recurrence, with their intact breast and with good cosmesis. Our survival rates and side effects were in consistent with literature, and RT is an effective option for DCIS patients following BCS.