Carotid blowout syndrome (CBS) refers to the clinical signs and symptoms related to rupture of the carotid artery (CA) and its branches, which mainly results from malignant invasion of the CA by head and neck cancers. Here, we present a 46-year-old male patient who suffered from nasopharyngeal carcinoma and was treated with a combination of chemoradiation and cetuximab. The patient was stage IVb (T4N2M0) clinically, with encasement of the left internal carotid artery, as shown on pretreatment magnetic resonance imaging. Three months after completion of radiotherapy, the patient died of sudden massive epistaxis. CBS is a lethal complication of nasopharyngeal carcinoma, so the risk of CBS should be carefully assessed in patients with imaging showing CA encasement. Till now, the precise prediction and prevention of CBS remain to be explored.