This study contributes insights into the ethical challenges that Taiwanese auditors face when conducting audit engagements. The study contains two main components. First, an experiment is used to assess the subjects' level of ethical reasoning in audit-specific contexts. It finds the ethical reasoning level of Taiwanese accounting students to be similar to that of their U.S. counterparts, whereas that of Taiwanese auditors is below that of the Taiwanese students. This set of findings, in turn, gives impetus to interviews with 23 experienced auditors to unearth the major ethical challenges that they have to contend with in audit engagements. The interviews suggest that Taiwanese auditors consider their primary professional obligation to be serving investors and the capital markets, and they seek to be conscientious in discharging this professional responsibility. But in doing so, they face a variety of challenges that range from limited personnel and time, to insufficient authoritative guidance, to client attributes and actions.