The Association of Southeast Asian Nations or ASEAN was established on 8 August 1967 in Bangkok by the five original Member Countries, namely, Indonesia, Malaysia, Philippines, Singapore, and Thailand.  Brunei Darussalam joined on 8 January 1984, Vietnam on 28 July 1995, Lao PDR and Myanmar on 23 July 1997, and Cambodia on 30 April 1999.

http://www.asean.org/

ASEAN National Secretariats
H.E. Mr. KAN Pharidh
Director-General, ASEAN-Cambodia
General Department of ASEAN
Ministry of Foreign Affairs & Int’l Cooperation
No. 161, Preah Sisowath Quay, Phnom Penh,
Kingdom of Cambodia
Tel#: (855)  23  213-247
Fax#: (855)  23  215-541; 216-144; 216-939
E-mail:   aseancambodia@online.com.kh