Purpose Suppressor of cytokine signaling 1 (SOCS1) is an intracellular protein that negatively regulates the Janus kinase(JAK)/signal transducer and activator of transcription (STAT) signal transduction pathway.SOCS1 was demonstrated to play important negative role in fulminant hepatitis and might involved in liver failure associated with hepatitis B virus (HBV) infection.This present study was therefore to identify the potential role of SOCS1 and its promoter methylation pattern in the patients with acute-on-chronic hepatitis B liver failure (ACHBLF).