Advances in measurement have allowed researchers to empirically distinguish between explicit attitudes, which are conscious and controllable, and implicit attitudes, which are activated automatically without cognitive effort or even awareness. Researchers using these methods have shown that although survey data reveal unprecedented declines in Americans’ expressions of overtly racist attitudes, most Americans continue to harbor an implicit pro-White bias relative to other racial minority groups. This research has generated a great deal of controversy. The primary focus of the controversy has been on the findings that have come out of studies using the Implicit Association Test or IAT – a response-time computer software program that records the speed with which positive and negative evaluations of different racial groups come to mind. This paper addresses the following questions that continue to divide researchers: (1) What does the IAT measure? (2) How do implicit attitudes as measured by the IAT relate to people’s race-related judgments and behaviors? (3) What are the political and legal implications of being able to measure implicit racial bias?