The aim of this study was to determine whether calcitonin gene-related peptide (CGRP) colocalizes with 5-HT(1F) receptor in rat vestibular nuclei using a double immunohistochemical staining procedure. The frequent co-occurrence of migraine and balance disorders suggests a pathophysiologic link between the two. However, the mechanism of migrainous vertigo has not been elucidated, though serotonin (5-HT) and its receptors are believed to involve in the pathogenesis of migrainous vertigo. Furthermore, 5-HT(1F) receptor agonists and CGRP receptor antagonists have recently attracted attention as potential treatments for migraine, and CGRP release from trigeminal neurons has been associated with migraine. This study demonstrates the colocalization of 5-HT(1F) receptor and CGRP in the rat vestibular nuclei, which suggests that 5-HT(1F) receptor regulates the release of CGRP from vestibular nuclei. This finding indicates that 5-HT(1F) receptor agonists may ameliorate migrainous vertigo by attenuating elevated levels of CGRP release from vestibular nuclei.