INTRODUCTION: Increased hospitalization is a major component of dementia impact on individuals and cost, but has rarely been studied in dementia with Lewy bodies (DLB). Our aim was to describe the risk and duration of hospital admissions in patients with DLB, and compare these to those in Alzheimer's disease (AD) and the general population. METHODS: A large database of mental health and dementia care in South London was used to assemble a cohort of patients diagnosed with DLB. These were 1:4 matched with patients diagnosed with AD on age, gender, and cognitive status. RESULTS: Rates of hospital admissions in the year after dementia diagnosis were significantly higher in 194 patients with DLB than in 776 patients with AD (crude incidence rate ratio 1.50; 95% confidence interval: 1.28-1.75) or the catchment population (indirectly standardized hospitalization rate 1.22; 95% confidence interval: 1.06-1.39). Patients with DLB had on average almost four additional hospital days per person-year than patients with AD. Multivariate Poisson regression models indicated poorer physical health early in the disease course as the main driver of this increased rate of hospitalization, whereby neuropsychiatric symptoms additionally explained the higher number of hospital days. DISCUSSION: Patients with DLB are more frequently admitted to general hospitals and utilize inpatient care to a substantially higher degree than patients with AD or the general elderly population. These data highlight an opportunity to reduce hospital days by identifying DLB earlier and providing more targeted care focused on the specific triggers for hospitalization and associations of prolonged stay.