Background: Prognostic studies in the context of Alzheimer's disease (AD) mainly predicted time to dementia. However, it is questionable whether onset of dementia is the most relevant outcome along the AD disease trajectory from the perspective of patients and their care partners. Therefore, we aimed to identify the most relevant outcomes from the viewpoint of patients and care partners. Methods: We used a two-step, mixed-methods approach. As a first step we conducted four focus groups in the Netherlands to elicit a comprehensive list of outcomes considered important by patients (n = 12) and care partners (n = 14) in the prognosis of AD. The focus groups resulted in a list of 59 items, divided into five categories. Next, in an online European survey, we asked participants (n = 232; 99 patients, 133 care partners) to rate the importance of all 59 items (5-point Likert scale). As participants were likely to rate a large number of outcomes as “important” (4) or “very important” (5), we subsequently asked them to select the three items they considered most important. Results: The top-10 lists of items most frequently mentioned as “most important” by patients and care partners were merged into one core outcome list, comprising 13 items. Both patients and care partners selected outcomes from the category “cognition” most often, followed by items in the categories “functioning and dependency” and “physical health.” No items from the category “behavior and neuropsychiatry” and “social environment” ended up in our core list of relevant outcomes. Conclusion: We identified a core list of outcomes relevant to patients and care partner, and found that prognostic information related to cognitive decline, dependency, and physical health are considered most relevant by both patients and their care partners.