This article describes the impact of street-level law enforcement on Australia's principal heroin market. Based on three years of research, including interviews and extended ethnographic fieldwork, it uses data on drug-use, risk practices, crime, and policing to examine the relationship between law enforcement and harm minimization. Findings suggest that the 'successes' of police crackdowns and their impact on drug markets (including threats to public health and community safety as a result of geographical, social, and substance displacement) may be won at substantial costs, raising doubts as to their value. This study is concerned with tensions in drug policing between commitments to law enforcement and to harm minimization, and with the harmful consequences to public health of the domination in policing practice of law enforcement. Reporting ethno- graphic research in Sydney's principal street-level drug market, and integrating perspectives from research in policing and in public health, we argue for a shift in policing priorities, rejecting suggestions that the law constrains the ability of police to subordinate law enforcement to other objectives. The focus is on the policing of drug users and user/dealers in public space. Such work is primarily carried out by uniformed patrol officers, although plain clothes officers also contribute. These activities have to be placed in the context of other forms of drug policing. During the study period, the research site was subject to the attention of a considerable variety of other police sections and agencies, including local detectives and drug units, regional and district specialists, transit police, the NSW Drug Enforcement Agency, the Australian Federal Police, and the National Crime Authority. These activities interrelated, overlapped, and sometimes conflicted. 1 Studies of drug policing often fail to discriminate except at a general level, for example between supply-side and demand-side strategies. This study indicates that more speci- ficity is needed because of the under-acknowledged importance of street-level enforce- ment (Pearson 1992). Despite the attention which specialist units attract, 'the current