Although the uptake of NSP has possibly reduced HIV transmission among injectors with shorter injection history, the prevalence of HIV among IDUs in four Indonesian cities remains unacceptably high. Sharing of injecting equipment is sustained by the fear of police arrests when carrying needles. Shifting emphasis from a security approach to a public health approach would contribute to reducing HIV transmission among IDUs in Indonesia. Sexual partners of IDUs are at high risk for getting infected with HIV and programmes should include strategies to this vulnerable population.