PURPOSE OF REVIEW: This review is intended to examine how the diagnostic criteria for migraine have evolved over the past 45 years and to evaluate the strengths and weaknesses of the current diagnostic criteria promulgated by the International Classification of Headache Disorders (ICHD). RECENT FINDINGS: The ICHD is a comprehensive and systematic classification system for headache disorders. As the pathophysiology of migraine is more fully elucidated and more sophisticated diagnostic technologies are developed (e.g., the identification of biomarkers), the current diagnostic criteria for migraine will likely be further refined. The ICHD has allowed for more precise research study design in the field of headache medicine. The current diagnostic criteria for migraine outlined in the 3rd version of the ICHD are far more sensitive and specific than the clinical criteria proposed in 1962. In future iterations, dividing episodic and chronic migraine into subtypes based on frequency (i.e., low frequency vs high frequency; near-daily vs daily) potentially could assist in guiding clinical management. In addition, a better understanding of aura, vestibular migraine, migrainous infarction, and hemiplegic migraine likely will lead to more refined diagnostic criteria for those entities.