Hepatitis B virus mutations may be associated with increased hepatitis B viral load and resistance to antiviral drugs. If hepatitis B virus mutations occur, it is recommended to seek medical attention to systematically assess the impact on the condition. Hepatitis B virus is a DNA virus, and mutations may occur during the process of viral replication. There are two types of mutations that have a greater impact, namely, those located in the precore region and the core region, which may be related to the increase in hepatitis B viral load and resistance to antiviral drugs. 1. Mutations in the precore and core regions cause the hepatitis B virus to be unrecognized by the immune system as it replicates, leading to higher viral loads, i.e., HBV-DNA levels. 2. Mutations in the precore and core regions may lead to resistance to antiviral drugs. Mutations are primarily resistant to interferon and nucleotide analogs, which may lead to higher rates of relapse and often require longer periods of treatment to suppress the virus.