Tenofovir alafenamide (TAF), a novel prodrug of tenofovir (TFV), has been approved for the treatment of chronic hepatitis B virus (HBV) infection. TAF has been shown to be a potent inhibitor of HBV replication at a low dose, with high intracellular concentration and more than 90% lower systemic TFV concentration than tenofovir disoproxil fumarate (TDF). TAF has been approved in the clinical practice guidelines in the west. Since its availability in Asia in 2017, there have been evolving data concerning its positive impact on renal safety as shown in registration trials. The primary objective of this study is to compare the risk of chronic kidney disease (CKD) progression in chronic hepatitis B patients on TAF versus ETV in a territory-wide cohort in Hong Kong.