Type 2 diabetes (T2D) and hepatitis C virus (HCV) infection are two global pandemics with a complex relationship. Extensive epidemiological and clinical data show that patients infected with HCV have a higher risk of developing insulin resistance (IR) and, in susceptible individuals, T2D. In patients with liver disease attributable to HCV, the presence of IR and especially T2D impacts major clinical outcomes such as incidence of hepatocellular carcinoma, liver-related mortality, fibrosis progression rate, response to antiviral therapy, and possibly the incidence of cardiovascular events. HCV patients with a liver transplant who develop IR or T2D also have worse clinical outcomes, although data are scarcer. We conclude with a few words on management and need for further research.