“Addressing HCV-related hepatocellular carcinoma: the current and future epidemics.” Hepatitis C virus (HCV)-related deaths now exceed HIV-related deaths in the US. Throughout the world, HCV is hyperendemic in people who inject drugs (PWID). New outbreaks of acute HCV infection are unfolding in HIV-positive men who have sex with men (MSM) and in 15-24 year olds who have transitioned from abuse of prescription opioids to illicit opiate injection. In patients with chronic HCV infection, 20-25% will develop liver disease which may manifest as cirrhosis, liver failure or hepatocellular carcinoma (HCC). The prognosis for HCC is extremely poor, and HCV is the chief etiologic agent for this type of cancer. Recent discoveries in HCV prevention and treatment provide a great opportunity to reverse the trend toward increasing rates of HCV, HCV/HIV co-infection, and HCC. This study will use the methods of Implementation Science – research synthesis, mathematical modeling and simulation, and comparative effectiveness analyses – to determine how best to constitute a portfolio of interventions for the prevention and control of HCV and its consequences while taking into account limited resources and underlying epidemiologic and social network features. A dissemination plan will make extensive use of technology, including social media, and guidance from key stakeholders.