Alzheimer's Disease and related disorders have recently become a priority in France and two consecutive governmental plans have been undertaken in 2001-2004 and 2004-2007. The number of prevalent cases was estimated to be 850,000 in France with an incidence of 220,000 cases. Only 50% of these cases were actually diagnosed and about 32% were treated by antidementia drugs. If the incidence and the duration of the disease do not change, the number of cases will increase to 1,200,000 in 2020 and 2,100,000 cases in 2040. In absence of curative treatment, the prevention way is necessary if one wishes to control this phenomena. The development of Memory Clinics and "Centres de Mémoires de Ressources et de Recherche" in all regions in France is one of the important measures to develop primary and secondary prevention in subjects with cognitive complaints or MCI. Several factors could be the basis of this prevention 1) Vascular risk factors (High Blood Pressure, Diabetes, Obesity, Hypercholesterolemiae, Tobacco consumption) ; 2) physical exercise ; 3) Stimulating cognitive activities ; 4) Nutrition ; 5) depressive disorders and loneliness.