The author examined the changing features of regional urban systems corresponding to changing regional structure in the last few decades with Hiroshima prefecture as case study. Especial attention was paid to clarifying the changing role of small towns. It was found that the Hiroshima metropolitan area had grown remarkably in recent years, expanding regional disparities between it and other areas. Hiroshima has also strengthened functional linkages to large centers within Hiroshima prefecture, particularly to Fukuyama. Because of the rapid growth of Hiroshima in such a small prefectural area, however, horizontal linkages between small and medium-sized cities to each other have hardly been developed. Unlike small towns in Western countries which grow in "amenity-rich" rural regions, most of them have been declining or, at best, stagnating under unfavorable conditions of living. But there are a few centers with small commuting areas, such as Yoshida and Joge. The growth of these centers could contribute to the improvement of living conditions in depopulated areas.