Objective: To identify the socio-economic and demographic factors associated with injecting drug users (IDUs) in Karachi.

Methods: We recruited 242 IDUs (taking drugs through sub-dermal routes) and 231 non-IDUs (taking drugs other than sub-dermal routes) from February through June 1996. IDUs were interviewed regarding sociodemographic factors, economic condition, and social network (marital status, living with spouse). In addition, information regarding location of drug users within the city (districts of Karachi) and current history of sexually transmitted diseases (STDs) were gathered. Moreover, blood samples were also obtained for HIV testing

.Results: Multivariate analysis showed that the income generation via illegal modes [AOR 1.6, 95% CI 1.0-2.6], non-sharing of income with family [AOR 1.7, 95% CI 1.1-2.7] and presence of suicidal thoughts [AOR 2.0, 95% CI 1.1-3.8] were associated with the use of drugs through injections. Further, drug users from districts West, East and Central were more likely to use drug through injection as compared to drug users from district South. The history of genital herpes was also found to be associated with injecting drug use. One IDU was found seropositive for HIV.

Conclusion: The high-risk behaviors, such as illegal modes of earning and presence of suicidal thoughts, among IDUs suggest that the group needs rehabilitation programme. Moreover, non-sharing of income suggest that IDUs are isolated from social network, therefore primary prevention activities with focus on improving socioeconomic conditions and social networking can reduce drug use through injections. Focused interventions on target districts would be helpful in reducing IDU (JPMA 53:511;2003).