Backgrounds: As the prevalence of dementia rises, caregiver burden also increases in South Korea, especially for informal family caregivers. Objectives: This study aimed to analyze factors affecting caregiver burden by the severity of dementia based on data of patients in Seoul. Methods: A total of 12,292 individuals aged ≥65 years enrolled in the Seoul Dementia Management Project from 2010 to 2016 in an online database were selected. Caregiver’s burden was assessed using the Korea version of Zarit Burden Interview.