The number of patients with young onset dementia (YOD) (that is before age 65) is estimated at 32,000 in France, and 5000 with onset dementia before 60 years. These patients differ from older ones by the greater number of rares causes (29%), heterogeneity of the presentation among the usual diseases, such as non-amnestic phenotypes of Alzheimer's disease, high frequency of frontal symptoms, and possible genetic origin. These aspects must be taken into account for the diagnosis, often more difficult than in older ones because patients have a little knowledge of the YOD, excepted in the genetics forms. YOD patients can still work or drive a car, and we should choose between the respect for autonomy and the security for the patient and their carers. YOD patients can be more often included in pharmacological trials because they have lower associated disorders. Individual non-pharmacological treatment should be priviledged because they don't easily accept collective activities with other patients over 60 years of age. Excepted for the very young patients (onset before 45), the survival is longer than in late onset dementia, with sometimes severe behavioral problems related to frontal syndrome. In France, the caregiving at home has been improved since the possibility for the YOD patients to receive a financial assistance reserved for the disabled patients, but admission to a nursing home before 60 is very difficult and increases the caregiver burden and perception of unfairness. There is a discrimination between young or older demented patients related to the great difficulty to meet the needs of younger patients, due to the rigidity of the medical and social systems. The presentation of a limited offer for the YOD patients must initiate reflections on our capacities to respect the autonomy and the dignity of the Alzheimer's patients regardless of age.