 Drug use DU is a major risk factor for HIV infection in many regions of the world. However, as highly active antiretroviral therapy HAART has been rolled out in South and South East Asia, less than 2 of individuals initiated on HAART were drug users DUs or former DUs, despite the fact that approximately 20 of HIV infections in the region are ascribed to DU. India is home to about 2.4 million HIV-infected individuals. Though, injection drug users contribute to only about 3 of all HIV infections in India; it is estimated that there are between 168,000 and 1.1 million DUs in India with HIV prevalence about 30. Novel approaches are needed to engage disenfranchised populations in HIV care in lower and middle income countries, where the burden of HIV disease is growing. Incentive-based strategies or contingency management have been shown to be effective in reducing illicit drug use, smoking cessation, and weight loss. Short-term pilot studies have also shown that incentive-based strategies can improve electronically-monitored rates of adherence to HAART in the US, and a recent study in Africa showed that a small incentive approximately doubled the rate that individuals returned to learn the results of their HIV test. However, to date there is no experience with the use of incentive-based interventions to improve engagement into care and risk-reduction among out-of-care HIV-infected DUs in developing world settings. The investigators propose to conduct pilot randomized trial comparing a voucher incentive strategy to a control condition to improve engagement in HIV care and HIV treatment outcomes among out-of-care, treatment-eligible, HIV-infected DUs in Chennai, India. Subjects in the incentive arm will be eligible to earn incentive vouchers for 1 initiating HAART at a government-sanctioned HIV treatment clinic, 2 adherence to scheduled follow-up visits at the HIV clinic, and 3 achieving suppression of HIV RNA. Subjects will be enrolled from a mature research venue in Chennai, YR Gaitonde Centre for Substance Abuse-related Research YRGCSAR, which focuses the epidemiology and natural history of HIV in DUs. Preliminary data from this pilot study will be used to inform the design of a phase-III study. 