The findings of our research show that while police play multiple roles in the fight against drug-related crime, they often perceived their tasks - especially preventing and controlling drug use on the one hand, and supporting harm reduction on the other - as contradictory, and this creates tensions in their work and relations with their communities. Although they are leaders and implementers of harm reduction, not all police know about it, and some remain skeptical or perceive it as contradictory to their main task of fighting drugs. Methadone treatment is seen by some as in competition with their main task of coordinating conventional drug treatment in the rehabilitation center.The history of drug use and the evolution of discourses on drug use in Viet Nam have created these conflicting pressures on police, and thus created contradictory expectations and led to different views and attitudes of police regarding various harm reduction measures. This might aid understanding why, despite the comprehensive and progressive policies on HIV/AIDS and harm reduction in Viet Nam, it is not easy for police to actively and effectively support and be involved in harm reduction at the ground level.To promote the wider acceptance of harm reduction the concept of community safety must be expanded to include community health; harm reduction must be integrated into the "new society" movement; and laws and policies need further revision to reduce contradiction between current drug laws and HIV laws.Harm reduction guidelines for police and other actors need to be disseminated and supported, embodying better ways of working between sectors, and all sectors in the partnership require support for building capacity to contribute to the overall goal.