Purpose: The purpose of this study was to identify the effects of intellectual capital in the relationship between social capital and organizational performance in hospital organizations. Methods: A cross-sectional design was used, with a convenience sample of 390 nurses from 3 general hospitals in Gwangju and Chonnam province. Data were collected through a questionnaire survey done from May 1 to 15, 2009. Data was analyzed with descriptive statistics, Pearson correlation coefficient and hierarchial multiple regression using the SPSS WIN 17.0 program. Results: There was a significantly positive relationship between social capital, intellectual capital and organizational performance. Intellectual capital showed partial mediating effects between social capital and organizational performance. However, intellectual capital did not show moderating effects. Conclusion: Accumulated social capital increased intellectual capital and the increased intellectual capital increased organizational performance. This finding suggests that as a contribution to the improvement of organizational performance in hospitals, creation and accumulation of social capital and intellectual capital are very critical.