Between 2004 and 2013, all the 63 FUAs of different sizes in Viet Nam grew much faster (at an average annual rate of 4.3%) than the FUAs in OECD countries on average (0.8%). While in OECD countries larger FUAs grew faster than smaller FUAs, Viet Nam showed a different pattern: both the three largest FUAs (Ho Chi Minh City, Ha Noi and Hai Phong, with a population of 1.5 million or more) and smaller FUAs (with a population of less than 200 000) grew faster (5.5% and 4.3%, respectively), compared to medium-sized FUAs. In the case of Viet Nam, it appears the country has seized the opportunity - as its urbanisation process has come together with strong increases in income levels.