Bulgaria joined the Organization on May 17, 1956.
Bulgaria actively participates in the process of strengthening cooperation in South-East Europe. In May 2005, for example, it organized with UNESCO a regional forum in Varna with the theme "Cultural Corridors in South-East Europe". It produced the Varna Declaration, whose signatories pledge to "contribute to the promotion of cultural heritage and cultural corridors within the region".
More than 50 Bulgarian schools are members of UNESCO's Associated Schools Project Network. There are also five UNESCO Chairs in Bulgaria, the most recent (1998) in Culture of Peace and Human Rights.
Bulgaria hosted the 2nd extraordinary session of the Intergovernmental Committee for the Safeguarding of the Intangible Cultural Heritage in Sofia in February 2008.