Aging of the population increases the number of people with dementia. Because of the lack of effective causal treatment, prevention of the conversion to the full-blown dementia becomes a priority. Researchers have focused on the identification of dementia risk factors, especially those which are susceptible to modification. Apart from the prevention of cardiovascular diseases, the most important are education, along with other components of cognitive reserve, and maintaining activity in old age. Of particular relevance is cognitive and social activity, the combination of which may significantly increase the effects of dementia prevention. Actions leading to the delay of the full manifestation of dementia should become widespread and promoted by specialists involved in care over dementia patients. They should become a part of the national programs in which attention to cognitive and social dementia preventive factors should be equal to general health factors. The paper discusses the importance of education, cognitive reserve as well as social and mental activity in delaying the manifestation of dementia clinical symptoms.