Substance abuse and addiction are highly prevalent in HIV-infected individuals. Substance abuse is an important comorbidity that affects the delivery and outcomes of HIV medical management. In this paper I will review data examining the associations between substance abuse and HIV treatment and potential strategies to improve outcomes in this population that warrant further investigation. Current - but not past - substance abuse adversely affects engagement in care, acceptance of antiretroviral therapy, adherence with therapy, and long-term persistence in care. Substance abuse treatment appears to facilitate engagement in HIV care, and access to evidence-based treatment for substance abuse is central to addressing the HIV epidemic. Strategies that show promise for HIV-infected substance abusers include integrated treatment models, directly observed therapy, and incentive-based interventions.