Soldiers carried the national flag towards the flagpole to prepare for the ceremony at 5.55 am.
At 6 am, the national anthem echoed across Ba Dinh Square and the flag was unfolded and hoisted to the top of a 29-metre pole.
Thousands of local people and visitors arrived early to attend the ceremony and then queued to pay tribute to President Ho Chi Minh in his mausoleum.
Ba Dinh Square is a national historic landmark where, on September 2, 1945, President Ho Chi Minh read the Declaration of Independence, giving birth to the Democratic Republic of Vietnam, now the Socialist Republic of Vietnam.
