The objective of this paper is to investigate changes in dementia mortality, as recorded on death certificates in Canada. Use is made of data available at Statistics Canada for the period 1990-1991. During this period there have been appreciable changes over time in the ages at death and in the percentage of death certificates that mention dementia. This increase in mortality associated with dementia can be explained, in large part, by an increased tendency for dementia to be listed as an underlying cause of death on the death certificate. Also, the median ages at death of persons in Canada for the period 1990-1991, for whom dementia is recorded as the underlying cause of death, are similar to or greater than the ages at death reported for all other causes of death but excluding dementia. Because those who have dementia are living longer, there is an increase in the number of people with dementia (prevalence of dementia); this has important implications concerning public policy on health and aging, We discuss the significance of these changes with respect to the future prevalence of dementia.