In Switzerland, because of the ageing of the population, the number of dementia's cases grows up. This represents a notable social and economic impact. The early detection is the key for a best patient's care. The general practitioner can use, in addition to his clinical approach, a certain number of screening tools in order to detect and diagnose dementia with an acceptable specificity and sensitivity (around 80%). Amongst these tools, we describe a four question questionnaire to the informants, the Mini Mental State Examination, the clock drawing test and the Mementool. A supplementary screening task, the 5 words test can orientate the diagnosis towards an Alzheimer disease or another form of dementia.