The World Health Organization (WHO) is a specialized agency of the United Nations (UN) that is concerned with international public health. It was established on 7 April 1948, with its headquarters in Geneva, Switzerland. WHO is a member of the United Nations Development Group. Its predecessor, the Health Organization , was an agency of the League of Nations.

The use of the word “world”, rather than “international”, emphasized the truly global nature of what the organization was seeking to achieve. The constitution of the World Health Organization had been signed by all 61 countries of the United Nations by 22 July 1946. It thus became the first specialized agency of the United Nations to which every member subscribed. Its constitution formally came into force on the first World Health Day on 7 April 1948, when it was ratified by the 26th member state. The first meeting of the World Health Assembly finished on 24 July 1948, having secured a budget of US$5 million (then GBP£1,250,000) for the 1949 year.

Andrija Stampar was the Assembly’s first president, and G. Brock Chisholm was appointed Director-General of WHO, having served as Executive Secretary during the planning stages. Its first priorities were to control the spread of malaria, tuberculosis and sexually transmitted infections, and to improve maternal and child health, nutrition and environmental hygiene. Its first legislative act was concerning the compilation of accurate statistics on the spread and morbidity of disease. The logo of the World Health Organization features the Rod of Aesculapius as a symbol for healing.

The WHO and the World Bank constitute the core team responsible for administering the International Health Partnership (IHP+). The IHP+ is a group of partner governments, development agencies, civil society and others committed to improving the health of citizens in developing countries. Partners work together to put international principles for aid effectiveness and development cooperation into practice in the health sector.

In addition, the WHO has also promoted road safety. Each year, the organization marks World Health Day focusing on a specific health promotion topic, timed to match the anniversary of WHO’s founding. Recent themes have been drug resistance (2011) and aging (2012). As part of the United Nations, the World Health Organization supports work towards the Millennium Development Goals. Of the eight Millennium Development Goals, three – reducing child mortality by two-thirds, to reduce maternal deaths by three-quarters, and to halt and begin to reduce the spread of HIV/AIDS – relate directly to WHO’s scope; the other five inter-relate and have an impact on world health.

The organization develops and promotes the use of evidence-based tools, norms and standards to support member states to inform health policy options. It oversees the implementation of the International Health Regulations, and publishes a series of medical classifications; of these, three are overreaching “reference classifications”: the International Statistical Classification of Diseases (ICD), the International Classification of Functioning, Disability and Health (ICF) and the International Classification of Health Interventions (ICHI). Other international policy frameworks produced by WHO include the International Code of Marketing of Breast-milk Substitutes (adopted in 1981), Framework Convention on Tobacco Control (adopted in 2003) and the Global Code of Practice on the International Recruitment of Health Personnel (adopted in 2010).

The WHO regularly publishes a World Health Report, its leading publication, including an expert assessment of a specific global health topic. Other publications of WHO include the Bulletin of the World Health Organization, the Eastern Mediterranean Health Journal (overseen by EMRO), the Human Resources for Health (published in collaboration with BioMed Central), and the Pan American Journal of Public Health (overseen by PAHO/AMRO).

As of 2013, the WHO has 194 member states: all Member States of the United Nations except Liechtenstein, as well as the Cook Islands and Niue. (A state becomes a full member of WHO by ratifying the treaty known as the Constitution of the World Health Organization.)

As of 2013, it also had two associate members, Puerto Rico and Tokelau. Several other entities have been granted observer status. Palestine is an observer as a “national liberation movement” recognized by the League of Arab States under United Nations Resolution 3118. The Holy See also attends as an observer, as does the Order of Malta. In 2010, Taiwan was invited under the name of “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, and, according to the WHO web site, “other countries may be admitted as members when their application has been approved by a simple majority vote of the World Health Assembly”. In addition, the UN observer organizations International Committee of the Red Cross and International Federation of Red Cross and Red Crescent Societies have entered into “official relations” with WHO and are invited as observers. In the World Health Assembly they are seated along the Financing and partnerships.

The WHO is financed by contributions from member states and outside donors. As of 2012, the largest annual assessed contributions from member states came from the United States ($110 million), Japan ($58 million), Germany ($37 million), United Kingdom ($31 million) and France ($31 million). The combined 2012–2013 budget has proposed a total expenditure of $3,959 million, of which $944 million (24%) will come from assessed contributions. This represented a significant fall in outlay compared to the previous 2009–2010 budget, adjusting to take account of previous under spends. Assessed contributions were kept the same. Voluntary contributions will account for $3,015 million (76%), of which $800 million is regarded as highly or moderately flexible funding, with the remainder tied to particular programs or objectives.