This study extends prior research of knowledge management by proposing how social capital can positively impact the ability of organizations to manage knowledge. The purpose of this study is to examine the relationship between social capital and knowledge management and how both help organizations achieve a sustained superior performance. To serve this purpose, I conducted an extensive survey on 143 Korean firms in diverse industries. Analyzing hypothesized relationships with the data collected, I empirically assure that organizations with high levels of social capital have more knowledge management capabilities than organizations with low levels of social capital and there exist statistically significant relationships between knowledge management and organizational performance.