['In patients with chronic hepatitis B virus (HBV) infection DNA levels do not always fall after anti-hepatitis B e (anti-HBe) seroconversion.', 'To follow longitudinally through HB e antigen (HBeAg) loss HBV DNA levels and core promoter/precore sequences in a cohort of 21 chronic HBV carriers.', 'Treatment-naïve HBeAg seropositive HBV carriers were monitored through HBeAg loss for between 2 and 22 years (mean 9.3). Core promoter/precore sequences, genotypes, HBV DNA levels and HBe status were determined.', 'Patients were grouped into those in whom serum/plasma HBV DNA remained high after HBeAg loss (group 1, n=11; HBV DNA>5log(10)IU/ml) and those in whom HBV DNA declined (group 2, n=10). Re-appearance of HBeAg was seen in seven group 1 patients. Pre-seroconversion mutations in the core promoter region including A1762T and/or G1764A were detected more frequently in group 1 (P=0.031). Overall sequence changes at sites other than 1762/1764 were more common post-seroconversion in group 1 than group 2 patients (P=0.037).'] Do presence of hepatitis B virus core promoter mutations pre-seroconversion predict persistent viral replication after HBeAg loss?