To check their opinions concerning the disclosure of the diagnosis of Alzheimer disease (AD), a questionnaire was sent to all neurologists and neuropsychiatrists currently active in Belgium, excluding neuropediatricians. Of 573 questionnaires, 44% were returned. Sixty-eight percent of the responders always announce the diagnosis to their patients, 24% prefer to reveal the diagnosis only to patients with mild dementia. Doctors who announce the diagnosis to all their patients and who believe that its a benefit for the patient (67%) were more likely to be younger, to be neurologists, and to speak Dutch. The most important arguments in favor of announcing the diagnosis were the patient's right to know and the reinforcement of the doctor-patient relationship. The main arguments against revealing the diagnosis were the patient's right not to know and fear of provoking a depression. Two-third of the participants informed the patients about the prognosis and natural evolution of AD. These doctors tended to be younger, to be neurologists, and to speak Dutch. Young doctors tend to be more “open” toward their patients concerning the diagnosis of AD, consistent with the current guidelines. The differences between Dutch and French speaking doctors might be partially due to the fact that in French, “démence” has a psychiatric connotation.