STUDY OBJECTIVE: We aimed to characterize clinical features, comorbidities, and polysomnographic characteristics of a large cohort of patients with narcolepsy. METHODS: We undertook a retrospective chart and polysomnographic review of all patients with a diagnosis of narcolepsy type 1 (NT1) or narcolepsy type 2 (NT2) seen within the Lehigh Valley Health Network between 2000 and 2022. RESULTS: We found 304 cases with a diagnosis of narcolepsy (52 NT1, 252 NT2), based on CONCLUSION: This is one of the largest monocentric studies to date of patients with narcolepsy and confirms the frequent comorbidities of narcolepsy. Specific clinical characteristics and comorbidities may help differentiate NT1 from NT2. CITATION: Jiang RY, Rochart R, Chu I, Duka S, Vendrame M. The Lehigh Valley Health Network Narcolepsy Cohort: clinical and polysomnographic analysis of 304 cases.