MediSave, introduced in 1984, is a national medical savings account system in Singapore. By law, all working Singaporeans and permanent residents must contribute 8-10.5% of their income to their MediSave account (MSA) to cover medical expenses for themselves or approved dependents, including hospitalization, day surgery, selected outpatient treatments, and healthcare needs in later years.

MediSave is part of Singapore’s three key healthcare schemes, collectively known as the 3Ms, alongside MediShield and MediFund. Managed by the Central Provident Fund (CPF) under the oversight of the Ministry of Health (MOH), MediSave is designed to encourage personal responsibility in healthcare financing.

On 1 April 1984, Goh Chok Tong, who served as Singapore's Second Prime Minister (1990–2004), introduced MediSave to encourage individuals, particularly young people, to accumulate personal savings for future healthcare expenses. MediSave is an integral part of the Central Provident Fund scheme, designed specifically for healthcare financing. Under this system, salaried employees are required to allocate a portion of their earnings to their MediSave accounts. Starting in 1984, CPF members could use MediSave to cover part or all of their hospital expenses at government hospitals, including up to 80% of Class A ward costs and full payment for other ward classes.

In 1985, private hospitals and the National University Hospital (NUH) joined the scheme. In 1986, MediSave coverage was extended to family members who were Singapore citizens or permanent residents. In 1988, MediSave was expanded to cover Hepatitis-B vaccinations and assisted conception procedures for couples. In 1989, it was extended to psychiatric treatment in private hospitals, renal dialysis, and radiotherapy. In 1990, eye surgery was included, followed by outpatient chemotherapy in 1991. In 1994, MediSave was further expanded to cover day treatments at approved medical facilities.

The government's goal in implementing the MediSave system in the 1980s was to encourage personal responsibility for healthcare among Singaporeans and permanent residents.

In the 1990s, additional considerations emerged, including the system's potential to mitigate "moral hazards" typically associated with government-provided health coverage and private health insurance. A moral hazard refers to a situation where patients overuse medical services and doctors over-treat, as medical expenses are covered by a third party, leaving individuals with no direct financial consequences. This can lead to higher healthcare costs for the community. However, despite the intention to reduce moral hazard, health expenditure per capita increased from 11% to 13% annually after the introduction of MediSave in 1984. To ensure affordability, the government shifted its focus from personal responsibility to direct government control of healthcare as the cornerstone of Singapore's health policy in 1993. This shift was articulated in the 1993 White Paper, which stated: "The government has to step in to structure and regulate the health system, as market forces alone are insufficient." As a result, several government initiatives were introduced, including the imposition of price caps on all medical services in government hospitals.

For a salaried employee who is a Singapore Citizen or permanent resident, MediSave contributions are deducted from their monthly Central Provident Fund contributions. Both the employer and employee contribute a percentage of the employee’s monthly salary to the CPF account, with contribution rates varying by age.

Since January 1988, self-employed individuals earning over $6,000 per year have been required to contribute to MediSave, with contributions capped at an annual income ceiling of $72,000. The contribution rates, which vary based on age, are the same as those for employed individuals. However, self-employed individuals must cover both the employer and employee portions of the contributions themselves.