Race has long been recognized as playing a critical role in policing. In spite of this awareness, there has been virtually no previous research attempting to quantitatively analyze the issue. In this paper, we examine the relationship between the racial composition of a city's police force and the racial patterns of arrests and crime. Increases in the number of minority police are associated with significant increases in arrests of whites, but have little impact on arrests of non-whites. Similarly arrests of non-whites, but do not systematically affect the number of white arrests. The race of police officers has a less clear-cut impact on crime rates. It appears that own-race policing may be more effective in reducing property crime, but no systematic differences are observed for violent crime. These results are consistent either with own-race policing leading to fewer false arrests or greater deterrence. In either case, own-race policing appears more "efficient" in fighting property crime.