
Vietnam's Foreign Minister Pham Gia Khiem signed the instrument of ratification.
A ceremony to hand over of Vietnam's instrument of ratification to the Secretary-General of Asean took place at the sidelines of the Asean Finance Ministers Meeting in Danang, Vietnam, on April 4.
Vietnam is the fifth country to ratify the Asean Charter, following in the footsteps of Singapore, Brunei, Laos and Malaysia.
The charter, which sets out principals and rules for Asean's operation, is expected to help the association become a closer and more effective socio-political entity.
The charter, signed in Singapore last year, aims to commit the region's disparate nations to promote human rights and democratic ideals and sets out the principles and rules for members.
It also transforms Asean, 40 years after its creation, into a legal entity, which will give the group greater clout in international negotiations.
Asean's goal of setting up a common community, including an economic blueprint to transform the region into a single market with a unified production base and no tariffs by 2015, has helped make the region - and Vietnam - more attractive to investment.
The five remaining Asean members are expected to ratify the charter by the end of the year.