Introduction and objectives:Dementia is associated with a high burden of disease, impacting patients, families and society. Nevertheless, related epidemiological data is becoming outdated, given the difficulties of implementing costly and laborious fieldwork surveys. Data is also difficult to retrieve from health and social services’ information systems. Overall, we must improve the feasibility and validity of case definition regarding dementia and the assessment of caregivers’ consequences. The 10/66 Dementia Research Group diagnostic algorithm is a cross-culturally valid method(1). A ‘short 10/66’ was also validated(2), but not in Portugal. We intend to assess its feasibility and validity in Portuguese samples, using REDcap (a browser-based, metadata-driven software) in mobile devices. Additionally, we aim to assess dementia family caregivers’ subjective burden and psychological distress, contrasting primary care and hospital outpatient settings.Methods:A multicentre mixed-methods study will be conducted on fifty dyads of older people with dementia and their caregivers, plus 150 dyads of ‘controls’ and their close family members, as informants. The ‘short 10/66’ will be administered. Dementia caregivers’ assessments include the Zarit Burden Interview and Self-report Questionnaire. Quantitative analyses will estimate the sensitivity and specificity of the ‘short 10/66’ dementia case definition. Semi-structured qualitative interviews will be conducted with participants and research assistants, exploring their experiences with the assessment process; thematic analysis will then be used.Implications:We expect this study to facilitate the diagnosis of dementia and data collection in health/social services on a routine basis, which will potentially improve the feasibility and decrease the costs of epidemiological surveys and allow for prevalence monitoring in Portugal.