A 46-year-old male with xeroderma pigmentosum developed an intracranial malignant schwannoma originating from the second branch of the left trigeminal nerve. The tumor was subtotally removed and postoperative radiation therapy given, but the tumor recurred twice over 3 years, and extended to the third branch of the left trigeminal nerve and the ipsilateral facial nerve. Radical surgery and radiation therapy finally achieved a cure. This is the first case of malignant trigeminal schwannoma with xeroderma pigmentosum, although various other internal neoplasms including central nervous system tumors have been reported in xeroderma pigmentosum patients. Radical surgery and radiation therapy are effective for treating intracranial malignant schwannoma. Radiation therapy is considered safe for xeroderma pigmentosum patients.