There is a great challenge in identifying the early diagnosis of the Alzheimer's disease, which has become the most frequent cause of dementia in the last few years, being responsible for 50% of the cases in western countries. The main focus of the work is the development of a multicriteria model for aiding in the decision making on the diagnosis of the Alzheimer's disease. It will be made by means of the Aranaú Tool, a decision support system mainly based on the ZAPROS method. The modeling and evaluation processes were conducted based on bibliographic sources, questionnaires, and on information given by a medical expert. The questionnaires analyzed were based mainly on patients' neuroimaging tests and were tried under various relevant aspects to the diagnosis of the disease.