Hepatitis C (HCV) infection is one of major epidemiological, medical and social concerns in the modern world. In Poland, around 700 000 people have HCV, worldwide the number is as high as 200 million. Current treatment consists of pegylated interferon-alpha and ribavirin, but is limited by the resistance of the viral strains, adverse effects, and high costs. Since HCV infection is a major cause of liver cirrhosis and hepatocellular carcinoma, it is necessary to develop novel antiviral compounds with improved virological response and reduced toxicity. In this article, we describe the results of recent trials to fight the HCV infection using an antagonising miR-122 oligo-LNA probe in primates.