This paper explores how to increase public cooperation and support for police. To date, only a few studies have attempted to explore the role that procedural justice plays in shaping the public's willingness to assist police in crime control. The present study explores this much neglected field of research using both crosssectional survey data and panel data. The study finds that views about police legitimacy do influence public cooperation with the police, and that those who view the police as more legitimate are more likely to assist police to control crime. The key antecedent of legitimacy is procedural justice; those who are more likely to believe police use procedural justice in their dealings with the public are more likely to perceive police as legitimate.