The official currency is Dong. The Dong is non-convertible and at the time of writing trades at approximately 21,000 to USD. The US dollar, preferably crisp clean bills, is widely accepted among major shops and restaurants. Travelers checks can be cashed at authorized foreign exchange outlets and banks and require presentation of passport. There is normally a 2 to 5 percent transaction fee for cashing Travelers checks. Visa and Master card are becoming more accepted in many of the bigger hotels and restaurants, especially in the larger cities.
Make sure that the Vietnamese notes you receive are not torn, this because many shops and restaurants will not accept them. Also try not to change too much money at one time, as you will end up with a large wad of notes. The largest denomination is currently 500,000 dong (approx. US$ 25). The government introduced new 500,000 and 50,000 notes made from plastic (like Australian dollars), rather than the regular paper notes. In 2004 Vietnam introduced coins for smaller transactions. These are in the form of 200, 1,000 and 5,000 Dong. Other paper denominations include 2,000 5,000 10,000 and 20,000. Most are clearly identifiable by color.
There are a number of international banks operating in both Hanoi and Ho Chi Minh City with 24hour cash withdrawal facilities, including ANZ Bank in Hanoi and the HSBC in Ho Chi Minh City. Here cash can be withdrawn on Visa and Master cards as well as other cards such as Cirrus. Please note that the Vietnamese Dong is non-convertible outside Vietnam.