Dermatofibrosarcoma protuberans (DFSP), a fibrohistiocytic tumour of intermediate malignancy, has a strong tendency to recur locally. Wide local excision is the recommended treatment modality. A retrospective analysis was performed on 38 consecutive DFSP patients presenting to The Netherlands Cancer Institute, to define the role of radiotherapy. Of the 21 patients treated surgically (all with negative resection margins) seven recurred, a local control probability of 67%. Combined modality treatment was given to 17 patients. Prior to radiotherapy, these patients experienced 33 occurrences of DFSP, but after irradiation only three recurrences were seen, a local control probability of 82%. These results are in keeping with the recent literature where increasing value is being given to both adjuvant and curative radiotherapy in the local management of DFSP. We recommend radiotherapy in DFSP patients where repeated surgery may cause mutilation or functional impairment.