|The main purpose of this article is to analyze the managerial performance of small and medium-size hospitals that are specialized in certain areas of medical services. Data of 189 hospitals were obtained from the data file of Korea Institute of Health Services Management. The items include general characteristics of the hospitals, financial reports, and utilization records. Degree of specialization is measured by concentration(Herfindahl) index, and the sample hospitals are accordingly classified into specialized and unspecialized groups, by means of cluster analysis. These groups are compared in terms of various measures of managerial performance, which include several profitability indices such as operating margin, return on assets(ROA), and return on equity(ROE). To examine the relationship between specialization and managerial performance, we estimate the regression model, where the profitability indices are used as the dependent variables and the concentration index as the independent variable, controlling for the hospital characteristics such as size, type and location. Also, we perform `Du Pont` analysis, to investigate the basic elements that can explain the differences in profitability between specialized and unspecialized hospitals. Major findings are as follows : 1. Managerial performance is better for the specialized hospitals than the unspecialized, in all aspects of profitability(operating margin, ROA, ROE). 2. Regression analysis suggests that there is a positive, statistically significant relationship between the degree of specialization(i.e. concentration) and hospital profitability. 3. Main reason for the higher profitability of specialized hospitals lies in lower expenses rather than higher revenue. 4. In particular, personnel and material expenses are significantly smaller for the specialized hospitals, and this result seems to stem from the efficiency of operating fewer lines of business. (some kind of `economies of scale`) 5. Specialized hospitals also have fewer employees compared with the unspecialized, especially in administrative departments, which implies their efficient personnel management.