As the largest and fastest growing emerging market, China is becoming more and more important to investors throughout the world. The purpose of this paper is to investigate the determinants of firms' auditor choice in China in respect of their corporate governance mechanism. Normally firms have to take a trade-off in their auditor choice decisions, i.e., to hire high-quality auditors to signal effective audit monitoring and good corporate governance to lower their capital raising costs, or to select low-quality auditors with less effective audit monitoring in order to reap private benefits derived from weak corporate governance and less-transparent disclosure (the opaqueness gains). We develop a logit regression model to test the impact of firms' internal corporate governance mechanism on auditor choice decisions made by IPO firms getting listed during a bear market period of 2001-2004 in China. Three variables are used to proxy for firms' internal corporate governance mechanism, i.e., the ownership concentration, the size of the supervisory board (SB), and the duality of CEO and chairman of board of directors (BoDs). We classify all auditors in China into large auditors (Top 10) and others (non-Top 10), assuming the large auditors can provide higher quality audit services. The empirical results show that firms with larger controlling shareholders, with smaller size of SB, or in which CEO and BoDs chairman are the same person, are less likely to hire a Top 10 (high-quality) auditor. This suggests that when benefits from lowering capital raising costs are trivial, firms with weaker internal corporate governance mechanism are inclined to choose a low-quality auditor so as to capture and sustain their opaqueness gains. On the other hand, with improvement of corporate governance, firms should be more likely to appoint high-quality auditors. © 2009.