The Purpose of this study is to estimate urban and regional agglomeration economies and to compare agglomeration economies among the cities and industries. The analytic model is Translog Production Function added to regional productivity function. The main results of this study are as followings. First, the bigger city size is, the greater agglomeration economies are. The agglomeration economies were decreasing in Seoul, but increasing in cities as year going. The differences of agglomeration economies between the developed city and the developing cities were decreasing as year going. Second, urbanization economies were decreasing in case of Nonferrous metal industry and Miscellaneous manufacturing industry in Seoul. Localization economies were also decreasing in case of Leather and fur products, Funiture products and Nonmetallic products in Seoul. This facts mean that external economies as ubanization economies and localization economies were smaller than excternal diseconomies in case of above mentioned industries in Seoul. Third, with the respect of scale of economies. Large scale firms are more efficient than small scale firms in every region. In spite of above facts, agglomeration economies in developed city are greater than in developing and underdeveloped cities. Thus concentration of economic activity in developed city like Seoul will be continued. Therefore it is good strategy for diminishing regional disparity that the large firms are located in developing countries like the Country wide cities.