The conversion rate of cognitive impairment to Alzheimer's disease is 1 to 25% per year. Early detection of cognitive impairment will thus become a major concern, particularly when pharmacological intervention for preventing or delaying conversion will prove effective. If simple carotid artery intima media thickness (IMT) measurements were to predict cognitive impairment, IMT could become one of the detection tools, as it is inexpensive, reliable and non-invasive. Since no review paper on this subject is available, a systematic review of the literature was performed. Twenty studies were identified evaluating the association between IMT and cognitive impairment and fourteen found a significant association after multivariate analysis. However, currently no definitive evidence of an association between increased IMT and cognitive impairment can be established. A consensus regarding the precise definition of cognitive impairment, and standardized methods to assess early cognitive impairment alongside a consensus for IMT measurement are needed in future epidemiological studies on the relationship between IMT and cognitive impairment.