In identifying a workable definition of juror impartiality, this paper considers what the legal system means when it uses the term, what the term should mean, and whether the qualities which make for an impartial juror can be identified. These issues are addressed by first reviewing common law conceptions of impartiality and relevant U.S. Supreme Court decisions. Neither the common law nor the Supreme Court has adequately dealt with the concept, so this paper proposes an alternative approach based on a more psychologically sophisticated view of human nature and on the underlying theoretical goals of the legal system in seeking an impartial jury. The paper concludes that given the adversarial orientation of opposing attorneys in a trial, they cannot be expected to commit themselves to the selection of an impartial jury. Although arguing that judges are best situated to select an impartial jury, the author reasons that judges currently lack adequate tools to perform this responsibility. The paper advises that social science methodology, currently used by trial attorneys to frustrate the search for an impartial jury, has the potential for enabling judges to impanel an impartial jury. 257 footnotes.