Background. This study elucidates the profiles for hepatitis B virus (HBV) reactivation and genetic mutation of the core promoter and precore regions for HBV-carriers receiving hematopoietic stem cell transplantation (HSCT). Methods. Sera from 20 HSCT patients diagnosed with hematological diseases, 13 donors and 36 healthy HBV-carriers, were collected regularly for analysis. The hepatic biochemistry profiles, serological HBV markers, and HBV-DNA titers were checked regularly, and primer-amplification of the HBV core promoter or precore region and sequencing were performed once the mutations were identified. Results. Deteriorated liver function was demonstrated for 13 of 20 post-HSCT patients, compared with none of the 36 controls (P<0.01). The HBV-DNA was detected more frequently for post-HSCT subjects than for controls (P=0.001). Incidence of the HBV precore nucleotide 1896 G-to-A mutation was significantly higher for HSCT patients (P=0.004), and a significant association was demonstrated for carriage of core promoter or precore mutations and the development of hepatitis (P=0.015). Different HBV genotypes were revealed in post-HSCT patients and the respective donors. Conclusions. Intensive chemotherapy and immunosuppression may cause HBV reactivation in HBV carriers receiving HSCT, and more frequent core promoter or precore mutations could be detected in HBV carriers receiving HSCT than healthy HBV carriers, with the chemotherapy/immunosuppression-induced immunocompromise possibly contributing to this effect. Donor HBV genotype did not interfere with that of the recipient after HSCT. Core promoter or precore region mutations were associated with a higher incidence of liver dysfunction than wild-type HBV carriers in the HSCT patients.