There is general consensus in the research literature that market orientation is related to organizational performance. The study examines this relationship in the Korean hospital industry. One feature of this study is to examine the differences between large and small hospitals in terms of their market orientation, performance and the relationship between these constructs. The other feature is that both market orientation and performance are conceptualized as being multi-dimensional constructs. Hence a structural equations modeling (SEM) technique is used to examine the dimensionality of market orientation and performance and to examine the nature of this relationship. Data for this study are collected using a questionnaire that is mailed to the top marketing-related managers of 1,048 hospitals. Usable responses are obtained from 230 hospitals for a response rate of 21.9%. The SEM results confirm the multi-dimensional nature of both market orientation and performance, and the strong relationships between the constructs. Interestingly, this relationship is found to be much stronger for smaller hospitals than for larger hospitals. For smaller hospitals, this study shows that market orientation has a tremendous influence on performance, with almost 73.9% of the variance in performance being attributed to market orientation.