Nucleos(t)ide analogues strongly inhibit viral replication in chronic hepatitis B (CHB) infection, but knowledge of their long-term effect on serum hepatitis B surface antigen (HBsAg) levels and HBsAg loss is lacking. Seventy-five CHB patients with virological response (VR) to ETV or TDF were included. HBsAg decline 2 years after VR was most pronounced in HBeAg-positive patients. Age, alanine aminotransferase, and HBeAg loss were associated with HBsAg decline in HBeAg-positive patients. Predicted median time to HBsAg loss was 36 years for HBeAg-positive and 39 years for HBeAg-negative patients. Thus, most patients treated with ETV and TDF will probably need decades of therapy to achieve HBsAg loss.