This study investigated the activities of the tensor and levator veli palatini muscles related to respiration. During quiet breathing, no activity was observed in either muscle. With either hypercapnic or hypoxemic condition, the tensor veli palatini muscle exhibited phasic activity during inspiration. The levator veli palatini muscle showed phasic activity during expiration with hypoxemia (PaO2 less than 40 mm Hg). NaCN perfused bilaterally through the carotid sinus induced these respiratory activities. The tensor veli palatini muscle was more sensitive than the levator veli palatini muscle to NaCN.