Purpose: This chapter examines some of the dilemmas involved in policing immigrant communities. Methodology: The chapter is based upon the relatively limited research literature on policing immigrant communities, an ongoing review of the contemporary dynamics of this issue in cities and states using the Internet, and original research in Chicago where a large and rapidly growing immigrant Latino community offers examples of most of the observations made by others. Findings: The chapter first examines some of the barriers limiting the ability of local police to work effectively in heavily immigrant areas. It then describes how these barriers are exacerbated by the presumed presence of significant concentrations of unauthorized migrants as well as legal residents. Demands that local police in the United States become more involved in enforcing immigration laws have become a point of great contention because this involvement runs at cross-purposes with community policing and other strategies to engage more closely with the community. Research implications: The magnitude of this conflict is illustrated by current debate over "sanctuary cities." These are communities where local officials have resisted the enforcement priorities of the federal government, and have continued to emphasize the role of the police in serving all residents.