Advanced dementia is the longest and most burdensome phase of the disease, marked by profound cognitive and functional impairment and high care complexity. In this descriptive, cross-sectional study, 252 older adults (≥60 years) meeting DSM-5 criteria for Major Neurocognitive Disorder with a Clinical Dementia Rating ≥2 were evaluated at their first visit to a specialized advanced cognitive impairment clinic in a Brazilian tertiary geriatrics service (2008–2025). The sample was predominantly female (66.3%), with a mean age of 79.1 years, low education (17.5% illiterate), and most living at home (89.3%). Clinical vulnerability was pronounced: low body mass index in 36.9%, dysphagia in 45.2%, polypharmacy in 75.8%, and antipsychotic use in 49.2%. Alzheimer's disease was the leading etiology (40.1%), and severe dementia predominated (71% CDR 3). These findings characterize a population of marked vulnerability and high care complexity managed predominantly in the community, underscoring the importance of locally generated data to inform practice and health policy in middle-income settings where home-based care prevails.