Alzheimer's disease (AD) is the most common cause of dementia in the elderly. Currently, 4.5 million individuals in the United States are estimated to have AD, and that number is projected to increase to at least 14 million by the year 2050. AD is a major cause of disability and mortality, and its impact on health care costs, including direct and indirect medical and social service costs, is estimated to be greater than $100 billion per year. AD typically presents with an insidious decline in memory that progresses to affect language, visuospatial perception, calculations, and executive functioning. Behavioral and psychiatric symptoms are also frequent in AD. Diagnosis is determined clinically, as there is currently no laboratory test to confirm AD in life. The neuropathologic hallmarks of AD are neuritic plaques and neurofibrillary tangles. Currently available medical therapies have demonstrated modest benefits but likely do not alter disease progression. Caregivers play a large role in managing the patient and should be encouraged to seek out adult day care centers, home health services, respite care, and additional social support.