The purpose of this study was to investigate HIV risk behaviours of IDUs and the drug scene in Bangladesh. The setting for the study was the city of Rajshahi, in the northwestern area of Bangladesh, which shares a border with India. Sixty-four clients of a drug treatment agency were surveyed about their drug use, drug injecting, sexual behaviour and knowledge about HIV and AIDS. All participants were males with a mean age of 32 years. Most participants had no or little formal education. All participants had injected drugs, primarily buprenorphine. The majority of participants were long-term drug users who had begun injecting drugs recently-70% had commenced injecting in the last 3 years. Sexual contact with sex workers (50%) and with casual partners (85%) was common among participants. Although most participants had heard of AIDS, few knew how HIV is transmitted. Most participants (81%) injected in groups at shooting galleries where they paid another to inject them. The shooting galleries operated without concern for hygiene or user safety. The potential for HIV to spread among IDUs and onto their non-injecting sexual partners in Bangladesh is cause for concern. A rapid assessment of HIV prevalence among IDUs in Bangladesh is urgently required.