Metabolic dysfunction-associated fatty liver disease (MAFLD) is prevalent in patients with chronic hepatitis B (CHB). The effect of the histologic MAFLD phenotype on long-term CHB outcomes is unknown. We performed a longitudinal study to determine the prognostic relevance of biopsy-proven hepatic steatosis and steatohepatitis for CHB patients. Clinical and laboratory data were obtained from CHB patients who underwent liver biopsy during 2002-2008 and were treated with antiviral drugs. A hepatopathologist reviewed the biopsy specimens. Cox proportional hazards regression was used to estimate the adjusted hazard ratio (aHR) of outcomes, including all-cause mortality, liver transplantation, and liver-related events. In accordance with Brunt's classification, 408 patients had steatohepatitis (n=34), "steatosis but not steatohepatitis" (n=118), or "non-steatosis" (n=256). All steatohepatitis patients had features of metabolic dysfunction. Over a mean follow-up of 13.8±3.1 years, 18 patients died or underwent liver transplantation. In multivariate-adjusted analysis, steatohepatitis (aHR, 6.37; 95% confidence interval [CI]: 1.59-25.5) compared with non-steatosis and advanced fibrosis (aHR, 11.3; 95% CI: 1.32-96.3) compared with no fibrosis were associated with overall mortality/liver transplantation. Thirty-five patients developed 43 liver-related events, among which 32 were hepatocellular carcinoma. These events were associated with steatohepatitis (aHR, 5.55; 95% CI: 2.01-15.3) compared with non-steatosis and advanced fibrosis (aHR, 6.23; 95% CI: 1.75-22.2) compared with no fibrosis. The steatosis but not steatohepatitis group had a non-significantly higher risk of overall mortality and liver-related events. Metabolic dysfunction-associated steatohepatitis increased the risk of long-term mortality/transplantation and liver-related events in CHB patients.