This paper applies the extended growth-factor decomposition method, which was developed by Akita (1999), to a three-region interregional I-O system consisting of the Kyushu region, the Kanto region, and all other regions in Japan to analyze the effects of regional characteristics and government policies on the growth patterns of the Kyushu region from 1965 to 1990. The Kyushu region, accounting for about 10 percent of the national economy, is regarded as an interesting case in regional economic development in Japan since its economy experienced a drastic structural change corresponding to changes in economic environment and government policies. The use of the three-region I-O system including the Kanto region also allows for an examination of the role of the Kanto region, which generates more than 40 percent of total gross domestic product and has exerted significant effects upon the rest of the nation, in the growth of Japan's regional economies. The extended growth-factor decomposition analysis based on the three-region interregional I-O system thus provides a better picture of the roles of interregional industrial linkages in the growth of Japan's regional economies. This paper analyzes changes in the pattern of regional economic growth over the period 1965-1990.