Telomeres, at the ends of chromosomes and strands of genetic material, become shorter as cells divide in the process of aging. Telomere length has been considered as a biological marker of age. Telomere length shortening has also been evidenced as the causable role in age-related neurodegenerative diseases, including Alzheimer's disease (AD). It has been demonstrated that telomere shortening has been associated with cognitive impairment, amyloid pathology and hyper-phosphorylation of tau in AD and plays an important role in the pathogenesis of AD via the mechanism of oxidative stress and inflammation. However, it seems that there is no relationship between telomere shortening and AD. Therefore, it is essential for further clarification of telomere-related pathogenesis in AD.