Despite advances in antiviral therapy for chronic hepatitis C, approximately half of patients undergoing initial treatment fail to achieve a sustained virologic response (SVR), thus prompting consideration of retreatment with alternative regimens. The decision to re-treat should be based on the severity of liver disease, as well as the presence of clinical and virologic predictors of a successful outcome of additional therapy. Retreatment of patients who were prior nonresponders to interferon monotherapy with interferon plus ribavirin results in SVR rates of 13% to 15%, which can be increased to 25% to 40% if peginterferon plus ribavirin is used. Retreatment of patients who were prior nonresponders to interferon plus ribavirin with peginterferon plus ribavirin unfortunately achieves SVR rates of approximately 10%. The growing number of patients who have been treated and have failed initial therapy highlights the need for the development of more efficacious antiviral agents for the treatment of chronic hepatitis C.