To assess physicians' attitudes toward the use of deception in medicine, we sent a questionnaire to 407 practicing physicians. The questionnaire asked for responses to difficult ethical problems potentially resolvable by deception and asked general questions about attitudes and practices. Two hundred eleven (52%) of the physicians responded. The majority indicated a willingness to misrepresent a screening test as a diagnostic test to secure an insurance payment and to allow the wife of a patient with gonorrhea to be misled about her husband's diagnosis if that were believed necessary to ensure her treatment and preserve a marriage. One third indicated they would offer incomplete or misleading information to a patient's family if a mistake led to a patient's death. Very few physicians would deceive a mother to avoid revealing an adolescent daughter's pregnancy. When forced to make difficult ethical choices, most physicians indicated some willingness to engage in forms of deception. They appear to justify their decisions in terms of the consequences and to place a higher value on their patients' welfare and keeping patients' confidences than truth telling for its own sake.