Background/Aims: An increasing number of antiviral drugs are being used to treat chronic hepatitis B virus (HBV)-infected patients. However, induced viral escape mutants -some potentially cross-resistant -lead to viral non-responsiveness and treatment failure. Effective treatment strategies must therefore take possible drug resistance (DR) into account with respect to monitoring and selection of alternative drugs. We evaluated the use of an updated INNO-LiPA HBV DR v2+v3 reverse hybridization assay versus sequence analysis to detect resistance mutations.