Alzheimer's disease is a neurodegenerative disorder with insidious onset and slow progression. Prevalence is increasing, although not as fast as previously believed. The clinical diagnosis may be difficult, but diagnostic methods have been introduced and proven to be accurate in supporting the clinical diagnosis. Application of these methods increases, partly due to improved awareness of cognitive symptoms and the relevance of early detection and diagnosis, in particular when more efficient disease-modifying drugs become available. Currently, only symptomatic treatment can be prescribed, and focus should be on potential prophylactic strategies.