|This study examines the relation between ownership structure and corporate perfoiinances in three Northeast Asian countries, namely, Korea, Japan and China. Specifically, the paper attempts to verify whether ownership structure is related to accounting corporate performances and technical efficiency. Our estimations indicate that ownership concentration in Korea has been positively related to profit margins, rates of return on shareholders` fund, total assets, capital employed, and corporate technical efficiency. For China, ownership concentration has been positively related to only profit margins and rates of return on total assets, while, in Japan, most of the corporate performance measures and technical efficiency are found to be unrelated to ownership concentration. These different effects of ownership concentration on corporate performances are thought to be the products of individual country`s histories and their social and commercial cultures, as well as their specific institutional, historical and technological settings.