The aim of therapy for the treatment of chronic hepatitis B virus (HBV) is to maintain suppression of viral replication to prevent the emergence of complications, which requires long-term therapy. Durable suppression of viral replication is achieved in the treatment of chronic viral diseases by preventing of the emergence of drug-resistant mutations. The clinical guidelines for the management of lamivudine resistant patients are variable. Some recommend switching to another agent without cross-resistance, while others recommend adding on another agent without cross-resistance. Limited clinical data exists to demonstrate whether tenofovir disoproxil fumarate (tenofovir DF; TDF) is an effective monotherapy for lamivudine resistant patients or if it should be used as part of a combination therapy regimen.