April 7, 1948

World Health Organization

WHO Constitution enters into force

WHO came into existence the moment a treaty threshold was crossed — the 26th acceptance — not when delegates signed its constitution nearly two years earlier.

Article 80 does the work

The Constitution of the World Health Organization entered into force on 7 April 1948 under its Article 80, which made it effective once 26 UN member states had ratified or accepted it. Deposits received by that date satisfied the threshold.

The Constitution had been signed on 22 July 1946 in New York, by representatives of 61 governments — 51 UN members and 10 other nations. The 1948 date is entry into force, not signature.

It was registered with the United Nations the same day as UN Treaty Series No. 221.

Governments made it, not the UN

The entry into force legally established WHO as the United Nations specialized agency for health. The shorthand that it was 'established by the United Nations' obscures the mechanism: governments created it through a separate multilateral constitution, following a conference convened under Economic and Social Council authority.

WHO acquired its constitutional mandate — including the definition of health as physical, mental and social well-being — from its first legal day.

Legal birth, operational handover

Day-to-day work stayed elsewhere for months. The pre-existing WHO Interim Commission continued handling operational tasks until the first World Health Assembly arranged its termination at midnight on 31 August 1948.

That Assembly opened in Geneva on 24 June, with 53 delegations from WHO's then 55 member states.

World Health Day was assigned to the anniversary later; the first observance came in 1950.

Sources

Researched 24 Aug 2026 7 sources not yet audited

How this was checked

Researched from the web into a fact sheet and rewritten from that sheet. This article has not yet had an independent model audit. How the pipeline works →

What the sources leave uncertain

The date and treaty mechanism are solid. The shorthand that WHO was simply “established by the United Nations” obscures that governments established it through a separate multilateral constitution, following a conference convened under UN Economic and Social Council authority.