This study explores two issues about police legitimacy. The first issue is the relative importance of police legitimacy in shaping public support of the police and policing activities, compared to the importance of instrumental judgments about (1) the risk that people will be caught and sanctioned for wrongdoing, (2) the performance of the police in fighting crime, and/or (3) the fairness of the distribution of police services. Three aspects of public support for the police are examined: public compliance with the law, public cooperation with the police, and public willingness to support policies that empower the police. The second issue is which judgments about police activity determine people's views about the legitimacy of the police. This study compares the influence of people's judgments about the procedural justice of the manner in which the police exercise their authority to the influence of three instrumental judgments: risk, performance, and distributive fairness. Findings of two surveys of New Yorkers show that, first, legitimacy has a strong influence on the public's reactions to the police, and second, the key antecedent of legitimacy is the fairness of the procedures used by the police. This model applies to both white and minority group residents.