Mixed dementia is caused by the combination of several simultaneous pathological processes, e.g., Alzheimer's disease and cerebrovascular pathology, Alzheimer's disease and dementia with Lewy bodies, cerebrovascular pathology and dementia with Lewy bodies etc. Many authors consider mixed dementia as the most frequent form of dementia in elderly people. Cholinesterase inhibitors, along with the modulator of glutamate receptors memantine, are commonly used for treatment of different types of dementia, in particular, Alzheimer's disease. Controlled studies have shown their effect in the treatment of dementia with Lewy bodies and vascular dementia. However, there are limited data on the efficacy and safety of the new antidementia drugs in treatment of mixed dementia. In this article, the approaches to the diagnosis of mixed dementia and possibilities of its treatment with cholinesterase inhibitors (donepezil) are described.