One of the important input information of policy making and socioeconomic planning work is future population size of the whole country and lower administrative units. Consequently, population projections are normally implemented periodically. However, population projections might also be done extraordinarily due to demands of the information users, particularly at the beginning of a new development period considered a turning-point. It is not an exception in the case of Vietnam that after each Population and Housing Census, population projections are made for many years later, serving the setting-up of long-term, medium and shortterm development programs.