A community survey and subsequent clinical assessment of 192 Cree aged 65 years and over registered in two Reserves in Northern Manitoba identified only one case of probable Alzheimer's disease among eight cases of dementia, giving a prevalence of 0.5% for Alzheimer's disease and 4.2% for all dementias. This contrasted with an age-adjusted prevalence of 3.5% for Alzheimer's disease and 4.2% for all dementias in an age-stratified sample of 241 English-speaking residents of Winnipeg. Although it was not so for all dementias, the difference between the groups for prevalence of Alzheimer's disease was highly significant (p < .001). The age-specific patterns of all dementias in the two groups were significantly different, however (p = .0254).