Socialized medicine is a pejorative term for publicly funded health systems, i.e. government-run hospitals and other healthcare providers or tax-funded health insurance. Supporters of this approach refer to it as National Health Services, universal healthcare, or "single payer healthcare".

The majority of developed countries have publicly funded health systems that cover the great majority of the population. For some examples, see the British and other National Health Service systems (e.g., medicare (Canada) and Medicare (Australia)).

The role of the government in healthcare provision is however a source of continued debate where opinions diverge sharply. The term "socialized medicine" is used mainly in the United States by people who are opposed to such systems. Economic liberalss in America oppose such systems because they involve government bureaucrats in what many Americans believe should be private decisions and tend to result in waiting lists for or even do not fund procedures that middle-class Americans consider fairly routine, such as MRIs for sports injuries, or elective angiograms. Proponents of a National Health Service regard limited availability of non-essential procedures as less important than the fact that such a service provides care more equitably, and ensures that a high level of care is available to all when it is essential. The difference of opinions about National Health Services is therefore not primarily one about facts, but about values.

It possible for medicine to be socialized in its funding but privately provided. For instance, United States healthcare for the elderly, also known as Medicare, is financed from taxation, but often provided by privately owned hospitals or physicians in private practice. In some systems, patients can also take private health insurance, but choose to receive care at public hospitals, if allowed by the private insurer.

From the inception of the NHS model (1948), public hospitals in the United Kingdom have included "amenity beds" which would typically be siderooms fitted more comfortably, and private wards in some hospitals where for a fee more amenity is provided. These are predominantly used for surgical treatment, and operations are generally carried out in the same operating theatres as the NHS work and by the same personnel. These amenity beds do not exist in other socialized healthcare systems, like the Spanish one, among others.

A political oscillation occurs in the UK and other countries where medical infrastructure has been partly socialized between separating private practice out into separate hospitals versus preferring to keep the consultants actually in the NHS hospital. Currently (in 2003) this favours separation and incompatibility.

From time to time the NHS pays for private hospitals (arranged hospitals) to take on surgical cases that the NHS facility does not have the capacity for. This work is usually, but not always, done by the same doctors in private hospitals.