Palestine overcame US and Israeli opposition to join the cultural body, with UNESCO saying that 107 member states voted in favor, 14 states voted against, with 52 abstentions.
The United States, Canada, Germany and Holland voted against Palestinian membership. Brazil, Russia, China, India, South Africa and France voted in favor. Britain and Italy abstained.
Palestinian officials hope success at UNESCO will boost their bid for admission as a member state at the United Nations, a proposal the Security Council is due to decide on Nov. 11.
The decision grants full membership to Palestine, which has had observer status since 1974; it allows the Palestinians to register certain sites, like the Church of the Nativity, in UNESCO's World Heritage register. Riad al-Malki, the Palestinian foreign minister, said the vote would help to "preserve cultural heritage in Palestine."