Introduction. Alzheimer's disease, as well as other dementias, cause a progressive deterioration of cognitive functions, preventing patients from making decisions and having control over themselves in an advanced stage of the disease. Objective. To explore some expectations, wishes and preferences in a sample of mature adults should they develop Alzheimer or other dementia. Method. We surveyed 368 mature Mexican adults without dementia using a large survey created by the authors and used in a previous study; data were collected in some public places where mature people were invited to participate. The survey was completed from July 2019 to August 2020. Results. Although most participants had considered they might suffer from dementia in the future, less than half had communicated their wishes to their relatives about future medical treatments in case they could no longer decide for themselves; very few had prepared a written advance directive. Most participants agreed that patients should know their initial diagnosis, mainly to be able to prepare themselves. The main reason given by those who would prefer to hide the diagnosis was to avoid suffering. Discussion and conclusion. Our results highlight the need for health professionals to promote discussion with people about the possibility of suffering from dementia, as well as the importance of making decisions in advance, and letting their relatives know about them.