Dermatofibrosarcoma Protuberans is an uncommon soft tissue tumor that is locally aggressive, prone to recur locally following excision, and has a low propensity for metastasis. Ten patients have received radiation (both external beam and interstitial implant) as part of, or as their only treatment, at Massachusetts General Hospital from 1979-1987. Three patients received radiation alone (66.7-75 Gy) for gross palpable disease. One patient has slowly regressing nodules at 33 months; the other two had complete regression and are free of disease at 24 and 26 months posttreatment. Seven patients received radiation in conjunction with surgery. One received both preoperative and postoperative radiation and six received postoperative radiation (60-67 Gy) for microscopic residual disease following resection. Six of these seven patients are free of disease 16 to 105 months following treatment. One patient, with diffuse microscopic tumor infiltration of the scalp, had a local recurrence within the radiation field 16 months following 64.4 Gy. There has been no significant treatment related morbidity. Even though the present experience is limited and the follow-up brief, it does suggest that radiation can be considered a viable therapeutic option in the patient who has a lesion that is not resectable.