There has been increased attention in recent years to the importance of individual privacy and professional confidentiality both in Australia and overseas. At the same time, psychologists' growing research interests in areas such as AIDS, child sexual abuse, and domestic violence have led to new ethical dilemmas over the contract of confidentiality between researchers and their research participants. The present paper discusses a number of issues regarding the ethics of confidentiality in psychological research. Following Bok (1989), the issues are highlighted within the context of four ethical principles that underlie researchers' obligations to preserve confidentiality. These principles are derived from considerations of privacy, loyalty, the pledge of silence, and professional codes of ethical standards. Each of these principles is illustrated with examples taken from recent research. We devote special attention to instances that appear to provide a clash between moral principles.