Background. In order to prevent the spread of the hepatitis C virus (HCV) amongst Hispanic injection drug users (IDUs), we developed, validated, and implemented a multimedia educational intervention program. Methods. A pre-post intervention study design was used to evaluate long-lasting knowledge and behavior changes in a group of 88 low-income Hispanic HIV-infected IDUs. Pre-intervention data was compared with data measured six months after the intervention. Results. A significant increase in the awareness regarding HCV clinical manifestations, HCV risky behaviors, HCV prevention practices, and HIV/HCV co-infection synergisms was observed in the group six months post-intervention. Conclusion. Our study confirms the long-lasting benefits of multimedia based intervention programs for disseminating HCV prevention strategies in IDUs. Preventive educational approaches that use images, figures, and animations tools can be recommended to target and tailor interventions for vulnerable populations.