Indonesia is facing one of the most rapidly growing HIV-epidemics in Asia. Risk behaviour associated with injecting drug use, such as sharing contaminated needles, is the main risk factor for HIV infection. Among the general population the prevalence of HIV-infection is still low (0.2%), but up to 50% or more of the estimated 145.000 - 170.000 injecting drug users are already HIV-positive. Overrepresentation of injecting drug users and continued risk behavior inside Indonesian prisons contribute to spread of HIV. Through sexual contacts, HIV is transmitted from current or previous injecting drug users to their non-injecting sexual partners; 10-20% of this group may already be infected. The national response targeted to limit spread of HIV through injecting drug use has included needle and syringe program (NSP), methadone maintenance treatment (MMT), voluntary counseling and testing (VCT), and outreach program as priority programs. However coverage and utilization of the harm reduction services is still limited, but effective integration with HIV testing and treatment is expanding. By 2008, there were 110 service points for NSP and 24 operational MMT clinics. Nevertheless, utilization of these services has been less satisfactory and their effectiveness has been questioned. Besides effective prevention, HIV- testing and earlier treatment of HIV-seropositve individuals, including those with a history of injecting drug use, will help control the growing HIV-epidemic in Indonesia.