The international business literature measures the link between the degree of internationalization (DOI) of a firm's activities and its performance. The results of this literature are mixed. This study attempts to describe the relationship between DOI and firm performance and extends the analysis to banks by using the bank-level data of China's five state-owned banks from the year of 1985–2009. DOI is measured by foreign assets/total assets(FATA) of 5 state-owned banks, bank performance is measured by return on assets (ROA). The results establish a positive, but weak relationship between DOI and bank performance. Then it discusses the policy implications of the analysis.