Psychologists' tasks in corrections involve entry-level and exit assessments of prisoners and involvement in their treatment. Confidentiality in correctional settings is subject to special pressures and raises the question of whether a meaningful relationship between a psychotherapist and a client is possible. Under these circumstances it is important for psychologists to specifically define client relationships in writing when dealing with individual clients and when accepting employment. Other issues concerning treatment ethics include the practice of behavior modification in which delivery of painful and occasionally harmful stimuli to prisoners has been attacked as unethical. A frequent solution to these and other ethical dilemmas is the use of a peer review committee to examine the professional adequacies of the procedures; a human rights review committee to look at the ethical and other implications of particular treatments; and a 'Promethean solution' which calls for full sharing with clients of all decisions and knowledge regarding professional activities. Ethical issues pertaining to research, psychologists' roles in class action suits, and a due process model are discussed. Statistical data, notes, and about 80 references are included.