Population changes in Thailand during the past two decades could really be referred to as revolutionary processes in population because of the rapid decrease of the rates of birth and death. This places the present national population increase rate at a point lower than the replacement level (Leoprapai, 1992). In the regional areas, although there is a similar trend, some differences could be noted especially in the Northeast where the population accounts for one third of the whole country, and where the physical conditions are not as fertile, causing problems of poverty more than in other regions. Population changes in the Northeast region are very important since they involve structural changes of age resulting from the decrease of fertility and death. In addition, the changes involve migration of population which is related to socio-economic development and the use of existing natural resources. Thus, in this article, the conditions of population changes in the Northeast will be emphasized which include use of the census of the years 1960 to 1990. The second ary data used were collected from the Population and Housing Census Authority, the Survey of Population Changes, various research reports, and relevant documents produced by different researchers. This assisted in the understanding of the changes of population in the regions, and the problems arising from such changes. The results should be useful for appropriate planning for future population changes.