This paper investigates the relationship between audit firms and the degree of clients' industry competition. Using the sample comprised of listed firms in Taiwan from year 1983 to year 2009, this paper explores the effect of the degree of clients' industry competition on the choices of audit firms. Furthermore, we examine the influence of the degree of clients' industry competition on the choices of individual auditors. This paper finds that the when clients' industry is more competitive, the client tends to avoid choosing the same audit firms which their competitors engages, even if the audit firms are attributed to industry specialization. In the context of individual auditors, we also find that the client not only avoids hiring the same audit firms but also the same individual auditors with their competitors.