This article examines the dilemmas posed by the involvement of expert witnesses in court cases and the institutional constraints on the ethics of expert testimony. The causes for the incorporation of bad science into legal decisions, potential solutions to this dilemma, and the limitations of these solutions are considered. Included among the possible solutions discussed are: changing the standards for the admissibility of scientific information; improving the factfinder's ability to assess adequately the credibility of experts and the validity of their assertions through the use of Special Masters; providing judges with independent experts or developing special protocols that spell out in detail the substance and sequence of questions a judge should ask lawyers and experts when faced with particularly complex or arcane scientific evidence; and providing cautionary instructions to jurors about the content and limits of the scientific knowledge. The role for scientific organizations and the use of ethical principles also are explored. Limitations on these solutions are noted. References