We describe a patient with an eyelid tumor that responded well to radiation therapy. The histopathological diagnosis was poorly differentiated sebaceous carcinoma. The patient received 52 Gy electron beam irradiation in a 5-week period; thereafter, the tumor diminished. The histopathological findings after radiation showed that most tumor cells underwent massive necrosis with hyalinized obstructive vessels. The tumor was under control at the 9-month follow-up examination.