Objective. Mixed dementia (MD), characterized by a combination of Alzheimer's disease (AD) and cerebrovascular disease, is one of the most common and, at the same time, poorly diagnosed forms of dementia in the elderly. The aim of our study was to investigate features of AD with its combination with cerebrovascular disease on the basis of clinical, neuropsychological and neuroimaging data. Material and methods. Authors examined 79 patients with dementia: 30 patients with AD, 33 patients with MD and 16 patients with vascular dementia. Patients with MD were older, had more often frontal gait disorders (48.5%), postural instability (45%), pseudobulbar syndrome (60%). Results and conclusion. The neuropsychological profile of patients with MD had mixed amnestic-dysexecutive character and, depending on the severity of vascular pathology, in some cases was closer to AD and in others to vascular dementia. A negative effect of vascular risk factors on medial temporal atrophy was found. Neuroimaging changes in MD were correlated with clinical manifestations. Proposed approaches to the diagnosis of MD help to determine more precisely the main directions of the treatment of patients and predict the course of the disease.