Vietnam's population will hit 90 million on the first day of November, making it the 14th most populated country in the world and the third in South East Asia.
Duong Quoc Trong, chief of the General Office of Population and Family Planning, said the figure showed that Vietnam had succeeded in reducing the birth rate, because in 1989, it had been forecast that the population would hit 90 million by 2002.
According to the office, Vietnam is enjoying a "golden population structure," meaning that for every two people or more working (15-64 years old), there is only one dependent person.
The period, which started in 2007, will last in 35 years, the office said.
Experts have said the period brings both advantages and challenge. They have noted that the rate of people who can read and write is high, but the rate of those who receive vocational training is low.
They said Vietnam is also facing emerging problems such as low population quality, increasingly aging society as well as gender imbalance at birth, with the current ratio at 112 boys per 100 girls..