To minimize impact of injection drug use on HIV/AIDS transmission, known as Harm Reduction, a longitudinal study on methadone maintenance substitution (MMS) trial was conducted in Drug Dependence Hospital, Jakarta in November 2003 and Sanglah Hospital, Denpasar in January 2004. Respondents of the study were 58 methadone clients from Jakarta 22 from Denpasar, as well as 11 RSKO’s staffs and se…