The World Health Organization (WHO) - Membership
UN members can join WHO by unilateral, formal notification to the UN secretary-general that they accept the WHO constitution. A non-UN member may be admitted if its application is approved by a simple majority vote of the World Health Assembly. Territories or groups of territories "not responsible for the conduct of their international relations" may be admitted as associate members upon application by the authority responsible for their international relations.
As of 2002, WHO had 192 member states.