Patients with dementia with Lewy bodies (DLB) have progressive deficits in cognition, parkinsonism, and neuropsychiatric symptoms. Cholinesterase inhibitors have been used to ameliorate cognitive decline and neuropsychiatric symptoms in short-term trials. In this study, patients with DLB were treated with rivastigmine up to 96 weeks. Improvement from baseline was seen in cognitive function as measured by the Mini-Mental State Examination (MMSE), and neuropsychiatric symptoms as measured by the Neuropsychiatric Inventory (NPI) over the first 24 weeks of treatment. By 96 weeks, neither the MMSE scores nor the NPI scores were significantly worse than at baseline.