APRI (aspartate aminotransferase [AST] to platelet ratio index) is widely used to assess fibrosis and cirrhosis risk, especially in hepatitis C virus (HCV)-infected patients. Few studies have evaluated APRI and hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) risk. Prospective evidence is needed to assess whether APRI predicts HCC risk in HBV patients.In a prospectively enrolled clinical cohort of 855 HBV patients with a 1-year exclusion window (followed for > 1 year and did not develop HCC within 1 year), the predictive value of APRI in HCC risk was evaluated by Cox proportional hazards model using univariate and multivariate analyses and longitudinal analysis.Higher APRI prospectively conferred a significantly increased risk of HCC in univariate analysis (quartile analysis, P trend = 2.9 × 10(-7) ). This effect remained highly significant after adjusting for common host characteristics but not cirrhosis (P trend = 7.1 × 10(-5) ), and attenuated when cirrhosis is adjusted (P trend = 0.021). The effect remained prominent when the analysis was restricted to patients with a more stringent 2-year exclusion window (P trend = 0.008 in quartile analysis adjusting all characteristics including cirrhosis), indicating that the association was unlikely due to including undetected HCC patients in the cohort, thus minimizing the reverse-causation limitation in most retrospective studies. Longitudinal comparison demonstrated a persistently higher APRI value in HBV patients who developed HCC during follow-up than those remaining cancer free.APRI might be a marker of HCC risk in HBV patients in cirrhosis-dependent and -independent manners. Further studies are warranted to validate this finding and test its clinical applicability in HCC prevention.