China's AIDS epidemic is mostlyconcentrated in high-risk populations, especially injectiondrug users and sex workers. Implementation of harm reductionprograms in China has expanded rapidly in the past fewyears. The government resources devoted to AIDS nearlytripled between 2004 and 2005, and have increased sixty-foldrelative to their level in 2000. This level of commitmentwarrants a careful examination of the efficiency with whichthese programs operate. As China's AIDS program isscaled up, issues concerning the allocation andeffectiveness of resource use are rapidly gaining importanceThe objective of the study is to present the cost andcost-effectiveness of harm reduction interventions inGuangxi Province to help policymakers and program staff tomount a well-targeted, cost-effective, evidence-basedHIV/AIDS prevention response. The study consists of twoparts. The first part is to compile and analyze theresources used and their costs for delivering harm reductionservices. The second part is to model the epidemic impact ofbehavioral changes produced by these HIV preventioninterventions. The study examined three types of harmreduction activities: methadone maintenance treatment (MMT);needle exchange programs (NEPs); and a program for sexworkers. Thus, identifying ways of increasing productivitymay be promising avenues for enhancing efficiency. Thecost-effectiveness analysis, based on an epidemic modelliking with behavioral parameters, found the needle exchangeprogram to be the most cost-effective of three interventionsexamined in this study.