To compare the prevalence of ageism in Canada and the United States, in Canada, the Ageism Survey was published in the CARPnews Report on Ageism, and in the United States, the Survey was administered to a convenience sample and published in the Center Report and Fifty Plus. Most respondents in both countries perceived ageism as frequent, but it was reported more often in Canada than in the United States. If the Ageism Survey is used to measure the prevalence of ageism among various groups and countries, we can develop an "epidemiology of ageism" and begin to reduce ageism.