Apathy, which has been attracting attention since Marin's report in 1990, is ubiquitous among neuropsychiatric diseases. It has a major impact on the quality of life in both patients and their caregivers and impairs rehabilitation and outcome. Furthermore, apathy is important as a prodromal syndrome in the development of dementia in mild cognitive impairment (MCI). We reviewed the neurobiological basis, prevalence and assessment of potential benefits of non-pharmacologic and pharmacologic interventions for apathy in MCI and dementia.