Background: The increasing imbalance between the number of older adults not working and the number of adults in the age range of labour force participation (age range 20-64) has long been a fundamental public policy challenge in the Organization for Economic Cooperation and Development member countries. At a societal level, this growing imbalance raises serious concerns about the viability and funding of social security, pensions and health programmes. At an individual level, the concern is probably more that of aging well with the prospect of many years in retirement. Some research suggests that retiring for some carries the risk of a fast decline in health. Volunteering can play a significant role in people's lives as they transition from work to retirement, as it offers a "structured" means of making a meaningful contribution in society once the opportunity to do so through work has been cut off. Some older people consider voluntary work as a way to replicate aspects of paid work lost upon retirement, such as organisational structure and time discipline. In many countries, volunteering of the older adults is increasing and programmes designed specifically for this subpopulation are emerging. Volunteering may contribute to both individuals aging well and society aging well, as volunteering by the older adults at the same time relieves the societal burden if it helps maintain health and functionality for those who volunteer. It thus remains to be established to what extent volunteering impacts on the physical and mental health of those who volunteer. Objectives: The main objective of this review is to answer the following research question: what are the effects of volunteering on the physical and mental health of people aged 65 years or older? Search Strategy: Relevant studies were identified through electronic searches of bibliographic databases, governmental and grey literature repositories, hand search in specific targeted journals, citation tracking, contact to international experts and internet search engines. The database searches were carried out to December 2018