Normal aging is accompanied by cognitive impairment with subtle cellular and molecular changes in the brain, whereas, pathological brain aging manifests as severe behavioral impairments with cellular pathology. Understanding the factors that contribute to both states is undoubtedly important for determining appropriate interventions that alter their progression. Mammalian target of rapamycin (mTOR) signaling has been implicated in affecting lifespan and age-related diseases such as cancer. The relationship of mTOR signaling with pathological brain aging has been more extensively studied, whereas the association with normal brain aging is not well understood. In this chapter we present information about normal and pathological brain aging, the relationship with mTOR signaling and use information from other age-related diseases to suggest that mTOR may have a role in promoting the cellular and molecular changes that underlie age-related cognitive changes. Future work should be directed towards understanding the precise role of mTOR signaling in brain aging. © 2016 Elsevier Inc. All rights reserved.