Most patients with thyroid carcinoma have a good prognosis. Due to the small number of fatal cases, it has not been clarified what conditions result in death for patients with thyroid carcinoma. To provide appropriate management for advanced thyroid carcinoma patients, we analyzed causes of death in 161 fatal cases. Clinical characteristics and immediate (final) causes of death based on pathological conditions were analyzed in 62 anaplastic carcinomas and 99 fatal differentiated carcinomas. Single fatal conditions could not be specified in 55 patients. In the remaining 106 patients, respiratory insufficiency (43%) was the most common specific fatal condition, followed by circulatory failure (15%), hemorrhage (15%), and airway obstruction (13%). Respiratory insufficiency due to remarkable pulmonary metastasis replacing lung tissue, massive hemorrhage and airway obstruction due to uncontrolled local tumors, and circulatory failure resulting from compression of the vena cava by extensive mediastinal or sternal metastases were found to be the most important immediate causes of death. Based on this knowledge, several palliative procedures may be worth considering to improve survival and quality of life in patients with advanced thyroid carcinoma.