This research article proposes a new multilayer Mamdani fuzzy inference system (ML-MFIS) to automate the diagnosis of hepatitis B. The system, called ADHB-ML-MFIS, classifies hepatitis B into no hepatitis, acute HBV, or chronic HBV stages. It has two input variables (ALT and AST levels) at layer 1 to detect liver conditions. Seven additional input variables at layer 2 (including HBsAg, anti-HBsAg, etc.) further determine the hepatitis condition output. The accuracy of ADHB-ML-MFIS in modeling hepatitis B processes according to medical experts is 92.2%.