BACKGROUND We assessed secular trends in the burden of ischaemic heart disease (IHD), stroke, and dementia in the Organization for Economic Co-operation and Development (OECD) countries. METHODS Using the Global Burden of Disease (GBD) Study 2017, we compared sex-specific and age-standardized rates of disability-adjusted life years (DALY); mortality, incidence, and prevalence of IHD and stroke; and dementia per 100,000 people, in the world, OECD countries, and Canada. RESULTS From 1990 to 2017, the crude incidence number of IHD, stroke, and dementia increased 52%, 76%, and 113%, respectively. Likewise, the prevalence of IHD (75%), stroke (95%), and dementia (119%) increased worldwide. In addition during the study period, the crude global number of deaths of IHD increased 52%, stroke by 41%, and dementia by 146% (9, 6, and 3 million deaths in 2017, respectively). Despite an increase in the crude number of these diseases, the global age-standardized incidence rate of IHD, stroke, and dementia decreased by -27%, - 11%, and - 5%, respectively. Moreover, there was a decline in their age-standardized DALY rates (- 1.17%, - 1.32%, and - 0.23% per year, respectively) and death rates (- 1.29%, - 1.46%, and - 0.17% per year, respectively), with sharper downward trends in Canada and OECD countries. Almost all trends flattened during the last decade. CONCLUSIONS From 1990 to 2017, the age-standardized burden of IHD, stroke, and dementia decreased, more prominently in OECD countries than the world. However, their rising crude numbers mainly due to population growth and ageing require urgent identification of reversible risk and protective factors.