It is important that we identify factors that could lead to interventions to slow cognitive decline in people with Alzheimer's disease. One potentially modifiable factor in Alzheimer's disease is disturbed sleep. The effect of disturbed sleep on cognition is of profound importance in people with Alzheimer's disease because disturbed sleep may worsen memory complaints. Therefore, the purpose of this article is to provide an updated review of literature that describes the impact of disturbed sleep on cognition in healthy populations and discuss the implications that this relationship has for people with Alzheimer's disease and their formal and informal caregivers.