Historically ignored or "treated," clients' religious beliefs are being incorporated into psychotherapy because they influence client and therapist thinking and have potential to heal and harm. This paper examines how professional codes of ethics and research on religion-friendly therapeutic interventions and on helpful and harmful religious beliefs and practices provide direction in dealing with religious matters in psychotherapy. Ethical codes emphasize self-determination, beneñcence, and nonmaleficence, whicb lead to different treatment decisions depending on how they are prioritized. The informed consent process and motivational interviewing have potential to ethically reduce harm and maximize benefits from the client's religious beliefs.