Disorders of cognition are a major societal burden. As the population grows and ages, these conditions demand urgent attention, as healthcare resources stretch to accommodate the growing number of patients. Although much is known about the neurobiology of dementia and Alzheimer’s disease (AD), few treatments are available to arrest or slow down the illness. By targeting specific structures within known circuits, deep brain stimulation (DBS) can have effects across memory and cognitive networks, and is therefore a potentially promising avenue for novel dementia treatments. This chapter reviews the literature on DBS for AD and dementia associated with Parkinson’s disease, and highlight some of the neuroanatomical targets that offer the most promise in modulating the underlying pathological activity in brain circuitry.