OBJECTIVES: Narcolepsy is a rare, chronic, central disorder of hypersomnolence characterized by excessive daytime sleepiness, hypnagogic/hypnopompic hallucinations, sleep paralysis, disrupted nighttime sleep, and sometimes cataplexy (Type 1). The objective of this study was to assess the prevalence of narcolepsy in a large representative general population sample in North America, Europe, and Asia. METHODS: This cross-sectional epidemiological study utilized data from the Sleep-EVAL research database. The study involved 61,754 participants from 10 countries interviewed between 1992 and 2016 using the Sleep-EVAL Expert System, an artificial intelligence system designed to conduct interviews and perform positive and differential diagnoses based on interview responses. Using the answers provided for each symptom, the expert system built its diagnostic tree to reach a diagnostic conclusion of narcolepsy type 1 (NT1) or narcolepsy type 2 (NT2) for each participant according to the International Classification of Sleep Disorders, Third Edition, criteria. RESULTS: Overall, the prevalence of NT1 was estimated to be 19.1/100,000 persons and the prevalence of NT2 was 23.3/100,000 persons. Prevalence of NT1 and NT2 was similar between countries and between men and women. Highest prevalence was among participants aged 35 years or younger for NT1 and among participants aged 35-54 years for NT2. CONCLUSIONS: Our study, based on data from the general populations of several countries, shows that narcolepsy is a rare disorder, affecting 42.4/100,000 persons.