Globally, it has been reported that nearly 257 million people suffer from chronic Hepatitis B virus (HBV). In Egypt, HBV has been classified as a moderate endemic where 4% of the population presented with chronic HBV. Long term Lamivudine (LMV) monotherapy has been found to develop resistant strains of HBV where the polymerase gene specifically is mutated (i.e., YMDD as a primary mutation). This review aimed to determine the correlation between LMV therapy and development of resistance in chronic HBV patients and to investigate the genes responsible for LMV resistance. LMV as an antiviral therapy has a fair response rate in the studied patients with 20% of the population has significant signs of mutation according to previous studies in Egypt . Unfortunately, the long duration treatment with LMV leads to development of LMV resistant mutations altering the efficacy of the drug and a rescue drug must be used immediately.

Keywords: HBV, LMV, YMDD, Mutation, Resistance.