The five agencies examined were the Metro-Dade Police Department (Miami), the Chicago Police Department, the Austin Police Department, the Kansas City Police Department, and the San Diego Police Department. Using an expert panel, the research staff developed a site protocol to guide on- site data collection. Information was collected through structured interviews with identified individuals within and outside the agency. Extensive documentation was collected through interdepartmental memoranda, news clippings, crime statistics, general orders, and other documents. The study found that gang problems and behaviors varied widely from city to city as well as within cities. This suggests the importance of crafting individual responses to gangs in accordance with their characteristics and behaviors. Types of criminal activity varied from gang to gang. There was no clear pattern of gang involvement in drug activity. The connection was only anecdotal and points to the need for additional research on this issue. Police consistently reported gangs to be less structured and organized than commonly believed. Consistent with a wide variation in gang problems was a similar variation in police responses to gang problems. Most of the departments used a combination of suppression, intelligence gathering, and investigatory strategies. Few agencies engaged in long-term planning or conducted research related to the nature of the problem; no agency provided extensive gang training to personnel or conducted any useful evaluations of the effectiveness of specific departmental efforts to counter gangs. Suggestions for additional research are offered. Tables and figures