OBJECTIVE To study the correlations between preS1 antigen, HBV-DNA and hepatitis B virus (HBV) serum markers in patients with chronic hepatitis B. METHODS The HBV markers, preS1 antigen and HBV-DNA were determined using enzyme- linked immunosorbent assay and quantitative PCR in 1158 patients with chronic hepatitis B. RESULTS In these patients, the HBV-DNA positivity rate was 68.9%, significantly higher than preS1 antigen positivity (54.8%, chi2=53.24, P<0.005). The positivity rates of both HBV-DNA and PreS1-antigen were significantly higher in HBeAg-positive patients than in HBeAg-negative patients (P<0.005). The coincident rates of preS1-antigen and HBeAg with HBV-DNA were 56.9% and 63.3%, respectively. PreS1 antigen had higher sensitivity but lower specificity than HBeAg. The detection rates of preS1 antigen and HBeAg increased with the level of HBV-DNA, and preS1 antigen positivity was higher than that of HBeAg in patients with low HBV-DNA levels. CONCLUSIONS Detection of HBV serum markers along with preS1 antigen and HBV-DNA may help assess the status of viral replication and therapeutic efficacy in patients with chronic hepatitis B. PreS1 antigen may serve as an auxiliary indicator in HBeAg-negative cases or when HBV-DNA detection is impossible.