Purpose: Patients with Lewy body dementia (LBD) may present a unique set of symptoms and challenges to family caregivers compared with other types of dementia. Prominent difficulties include motor impairment, activities of daily living (ADLs) disability, recurrent behavioral and emotional problems (BEPs), and diagnostic difficulties. These problems are likely to affect caregivers' subjective burden. Design and Methods: The present study used data from an Internet survey conducted by the Lewy Body Dementia Association. Respondents were 611 people who indicated that they were currently involved in the care of their relative with LBD. Subjective burden was assessed with a 12-item short version of the Zarit Burden Interview. Results: A factor analysis revealed 3 dimensions of burden: role strain, personal strain, and worry about performance. Multiple regressions were used to examine predictors of these dimensions. BEPs, ADL disability, isolation, caregiver age, and patient gender were significant predictors of specific factors. Falls, formal service use, difficulty finding a physician, and evaluation of the physician had no significant associations with burden. Implications: These findings highlight burden experiences by caregivers of patients with LBD and the impact of BEPs, ADL assistance, and awareness about LBD on subjective burden.