Background: The relationship between Built Environment and Dementia is nowadays a fundamental theme to investigate in the healthcare field because the elderly population is growing worldwide. Epidemiological data show that Alzheimer's disease incidence is forecast to increase rapidly. Furthermore, the health and socio-sanitary structures for elderly patients represent a fundamental social infrastructure that collects significant investments but must be suitable to host people with dementia. This paper aims to describe the application of a tool able to evaluate architectural design features in facilities for patients with Dementia. Methodology: The evaluation framework is based on a Systematic Literature Review on the relationship between the built environment and patients with dementia, different case studies, and existing evaluation tools analysis. The tool comprises four criteria (Quality, Spaces, Activities, and Wayfinding), 19 indicators, and 71 variables validated by recognized experts in the geriatric, psychiatry, and architecture field. The tool has been applied to five facilities, all accredited to the Italian National Health System and located in Lombardy that differ in period of construction and type. Results: The maximum score is 100%, and results lower than 60% are considered inadequate, between 60 and 80% are sufficient, and more than 80 excellent. The results of the evaluation tool show that two are inadequate (47 and 54% of compliance), two sufficient (65 and 75%), and one excellent (92%). The newest building was evaluated as “excellent”, while the structure with the lowest score was created by reusing existing structures. Future applications are needed to make the results more scalable.