Several authors have pointed out that in the next few decades dementia will affect a considerably increasing number of the elderly. To our knowledge there exist no calculations of the number of demented persons for the whole European region. We made calculations on the number of dementia cases for the period 2000–2050 based on the population projections of the United Nations. For this purpose, we used the results of several meta-analyses of epidemiological studies. The number of prevalent dementia cases in the year 2000 was 7.1 million. Within the next 50 years, this number will rise to about 16.2 million dementia sufferers. The number of new dementia cases per year will increase from about 1.9 million in the year 2000 to about 4.1 million in the year 2050. Contrarily, the working-age population will considerably decrease during the next 50 years. In the year 2000, 7.1 million dementia cases faced 493 million persons in working-age. This equals a ratio of 69.4 persons in working-age per one demented person. Until the year 2050, this ratio will decrease to only 21.1. Thus, the financial and emotional burden placed by dementia on the working-age population will markedly rise.