Chronic hepatitis C infection represents a significant and growing health problem worldwide. Patients with genotype 1 hepatitis C respond poorly to the current standard of care, pegylated interferon and ribavirin, which is frequently associated with unpleasant side effects. Consequently new agents with improved efficacy and tolerability are needed. The efficacy and safety of the direct-acting antiviral agent telaprevir in the treatment of genotype 1 hepatitis C infection have been demonstrated in a number of clinical trials. The addition of telaprevir to standard therapy considerably improves response rates and allows response-guided shortening of treatment duration in a substantial number of treatment-naïve patients. Side effects associated with telaprevir therapy include rash, anaemia, gastrointestinal disturbance and anorectal discomfort. Telaprevir-resistant variants have been identified in patients who have failed telaprevir-containing therapy, and whether selection of these variants will compromise future therapeutic options is currently unknown. The efficacy and safety of telaprevir in the treatment of the most challenging patients, including those with recurrent hepatitis C following liver transplantation and those co-infected with HIV, remains to be established.