The primary aim of this study was to investigate HIV infection among drug users. A total of 3538 drug users were, registered at the Outpatient Department of Central Drug Addiction Treatment Centre (CTC), Tejgoan, Dhaka, from July 2007 to June 2008. Of them, 43.2% were residents of Dhaka City and the others (56.8%) were from the different districts of Bangladesh. Among them, 1196 were recruited consecutively following defined selection criteria. Interviewer-administered questionnaires were completed and blood specimens taken. Results showed that only 0.67% were HIV-seropositive. Their socioeconomic profile included 75.0% educated, 62.5% unemployed, age ranged from 30 to 50 years, and all were married. They used heroin primarily with other illicit substances used occasionally. They reported that needle sharing when using injection drugs was infrequent. Drug users had sex with multiple commercial sexual partners and did not use condoms during sex. While Bangladesh is in the midst of international drug-trafficking and drug-producing zones, and lies near high HIV prevalence countries, the country is in the embryonic stage of an HIV epidemic. Nationwide preventive measures are warranted in Bangladesh.