Dementia with Lewy bodies was first recognized as a separate entity about 30 years ago. The prevalence varies from 0% to 5% in the general population, and this disease accounts for 0% to 30.5% of all dementia cases. Dementia with Lewy bodies is considered the second most common cause of degenerative dementia after Alzheimer's disease. The disease is characterized by alpha-synuclein immunoreactive protein deposits in both neurons and glial cells. The protein deposits are especially prominent in dopaminergic neurons, where they can be detected using conventional histological stains, such as hematoxylin and eosin, and are commonly referred to as Lewy bodies. The diagnosis of dementia with Lewy bodies is based on the presence of dementia as well as 2 of the following 3 core diagnostic features: 1) fluctuating cognition, 2) visual hallucinations, and 3) movement disorder. Diagnostic tests include laboratory data, structural and functional imaging, and electroencephalography. Differential diagnosis of dementia with Lewy bodies focuses on other later life dementia syndromes, other parkinsonian diseases (Parkinson's disease, progressive supranuclear palsy, corticobasal degeneration), and primary psychiatric illnesses. There is type 1b evidence to support treatment with cholinesterase inhibitors. Glutamatergic and dopaminergic therapies are used as well. Standard neuroleptics are contraindicated, and atypical agents should be used cautiously. Nonpharmacologic measures - therapeutic environment, psychological and social support, physical activity, behavioral management strategies, caregivers' education and support, and different services - could be suggested.