This study examines ethical issues faced by private investigators and commercial agents, and the implications for industry regulation. Interviews were conducted with 40 agents, covering their experiences of ethical challenges, perceptions of the conduct of colleagues, and ideas regarding the best form of regulatory control. The results indicate that a marked evolution has occurred in the last 30 years away from ‘personal work’ and towards large-scale anti-fraud work. This has brought private agents into the commercial mainstream, and contributed to enhanced respectability and improved, client-driven standards of conduct. Nonetheless, private inquiry work continues to present intrinsic ethical risks through the traditional conflict between perceived just ends and unethical or illegal means, combined with extensive operational discretion and limits on client or government supervision. The main areas of risk concern threats to privacy through access to confidential information and through intrusions into personal space, deceptive practices, and intimidation. A significant finding of this study was that interviewees reported high levels of ‘self-policing’ in managing these risks. Nonetheless, the large majority also felt that the risks entailed in investigation work were of sufficient magnitude to justify greater control of the industry by government. Interviewees also claimed that opportunities for misconduct could be reduced, and that they would make a greater contribution to crime control, if governments legislated for a more productive balance between justifiable requests for information and the protection of privacy.