Alzheimer's disease (AD) is a neurodegenerative disorder of the brain; its etiology remains unknown. It represents the most common form of dementia among the elderly, since over 60 % of the cases of senile dementia show the characteristic anatomo-pathological features of AD. The prevalence rate of AD is approximately 5 % amongst individuals aged 65 and over. The disease onset is generally after 60 and the risk of developing AD increases with age. In view of the phenomenon of ageing of our populations, the number of cases of AD should increase significantly in the future. The objective of this paper is to present the preliminary findings of the IMAGE Project on the geographical distribution of AD cases, based on their place of residence in one specific region of the province of Québec. We also present our initial measurements on the variations in prevalence rates between urban and rural areas. The establishment of the IMAGE registry of AD cases has been in progress since 1986 over the entire Saguenay—Lac-Saint-Jean territory; 221 possible, probable and definite cases have actually been screened. Working on the basis of six predefined geographical spheres of screening, the variation of standardized prevalence rates does not appear to be statistically significant. Only the spheres of Alma and of La Baie, with a comparative prevalence index greater than 1,0, show a trend for more cases, albeit not statistically significant. Moreover, the proportion of cases found in the sphere of Alma is largely rural.