The International Classification of Diseases (ICD-11) is the 11th edition of a global categorization system for physical and mental illnesses issued by the World Health Organization (WHO). Antonio Federico, MD, PhD, University of Siena, Siena, Italy, discusses the importance of the ICD-11, the first-ever global classification of diseases to consider rare diseases. The ICD-11 may be very useful in clinical practice as it helps develop a diagnostic process of rare neurologic diseases, resulting in early treatment and better patient care. Additionally, the ICD-11 will also help obtain epidemiology data. This interview took place during the XXV World Congress of Neurology.