Although not all patients develop progressive liver disease, chronic hepatitis B and chronic hepatitis C infections cause substantial morbidity and mortality worldwide. To address this need, many new antiviral treatments have become available over the past 10 years. While safety, efficacy, and therapeutic indications have been well established for these agents, the economics of antiviral treatment have become increasingly a focus of discussion for physicians, policymakers, and health payers. In this paper, we will elucidate some economic principles using examples from the treatment of hepatitis B and C. In particular, we will examine the considerations in estimating drug costs, methods for performing economic analyses and lastly summarize published cost-effectiveness analyses for antiviral treatments of chronic hepatitis B and chronic hepatitis C. This review should help clinicians understand economic issues regarding new drugs and answer questions about whether the clinical benefit provided by a medication justifies its expense.