The World Health Organization (WHO) is a specialized agency of the United Nations (UN) that acts as a coordinating authority on international public health.
Established on April 7, 1948, and headquartered in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health Organization, which had been an agency of the League of Nations.

The WHO's constitution states that its objective "is the attainment by all peoples of the highest possible level of health." Its major task is to combat disease, especially key infectious diseases, and to promote the general health of the people of the world.

The WHO has 193 Member States, including all UN Member States except Liechtenstein, and two non-UN members, Niue and the Cook Islands. Territories that are not UN Member States may join as Associate Members (with full information but limited participation and voting rights) if approved by an Assembly vote: Puerto Rico and Tokelau are Associate Members. Entities may also be granted observer status: examples include the Palestine Liberation Organization, Vatican City, and Chinese Taipei.

WHO Member States appoint delegations to the World Health Assembly, WHO's supreme decision-making body; all UN member states are eligible for WHO membership.

The WHO is financed by contributions from member states and from donors. In recent years, the WHO's work has involved more collaboration; there are currently around 80 such partnerships with NGOs and the pharmaceutical industry, as well as with foundations. Voluntary contributions to the WHO from national and local governments, foundations and NGOs, other UN organizations, and the private sector now exceed that of assessed contributions (dues) from the 193 member nations.

The six Regional Offices are:
- Regional Office for Africa (AFRO), with headquarters in Brazzaville, Republic of Congo. AFRO includes most of Africa, with the exception of Egypt, Sudan, Tunisia, the Libyan Arab Jamahiriya, and Morocco, which belong to EMRO.
- Regional Office for Europe (EURO), with headquarters in Copenhagen, Denmark.
- Regional Office for South East Asia (SEARO), with headquarters in New Delhi, India. North Korea is served by SEARO.
- Regional Office for the Eastern Mediterranean (EMRO), with headquarters in Cairo, Egypt. EMRO includes the countries of Africa, and particularly in the Maghreb, that are not included in AFRO, as well as the countries of the Middle East, except for Israel.
- Regional Office for Western Pacific (WPRO), with headquarters in Manila, Philippines. WPRO covers all the Asian countries not served by SEARO and EMRO, and all the countries in Oceania. South Korea is served by WPRO.
- Regional Office for the Americas (AMRO), with headquarters in Washington, D.C., USA. It is better known as the Pan American Health Organization (PAHO). Since it predates the establishment of WHO, PAHO is by far the most autonomous of the six regional offices.

The World Health Organization operates 147 country and liaison offices in all its regions. The presence of a country office is generally motivated by a need stated by the member country. There will generally be one WHO country office in the capital, occasionally accompanied by satellite offices in the provinces or subregions of the country in question.

Wikipedia, the free encyclopedia. World Health Organization. Internet. Accessed August 30, 2009.