Dermatologic malignancies are common in xeroderma pigmentosum (XP) patients; they can develop maxillary sinus cancers on rare occasions. Despite their extreme sensitivity to ultraviolet light, the patients of XP can be treated with standard doses of ionizing radiation for the treatment of cancers. The examples of use of radiotherapy as a treatment modality for maxillary neoplasms in patients of XP are rare. This report highlights a rare association of maxillary carcinoma in a patient of XP who received the tumoricidal doses of therapeutic X-rays with acceptable toxicities.