This paper reports the empirical evidence on the relation between family ownership and firm performance using the 1,616 non-financial firms at the Korean Stock Market. We find that the family ownership is a significant determinant of the firm performance. The family firms significantly outperform the non-family firms, and the performances in the young-family firms and the old-family firms are indifferent. We classify the family ownership into direct and indirect one which the indirect-family firm is governed by the affiliated companies. The indirect-family firms as well as the direct-family ones perform better than non-family firms. Our results provide the family firms are prevalent and effective business structure in Korea, and support the convergence of interest hypothesis.