To investigate the frequency of hepatitis B virus (HBV)-related events after allogeneic HCT in a moderate endemic area for HBV infection. The data of 197 patients who underwent allogeneic hematopoetic stem cell transplatation (HCT) from September 2003 through December 2010 were reviewed retrospectively with respect to HBV-related events. Resolved HBV infection was described as negative HBsAg, positive HBcAb, and positive HBsAb. Latent HBV infection was defined in patients with HBcAb positivity in the abscence of HBV DNA and HBsAb. Hepatitis B naive patients are defined as the patiens with no serological or molecular marker related to HBV. Seropositive patients were the patients with positive HBsAg and HBV-DNA. Median age was 28 (range, 15-64) years, with 128 male and 69 female patients. Median follow-up of the cohort was 8 (range, 0.5-78) months. We detected HBV-related events in 7 (3.6 %) recipients after allogeneic HCT. Five (71.4 %) of these events were HBV reactivation, while two cases (28.6 %) had acute hepatitis B infection. Four of the five reactivations were in the seropositive group (80 %), while one ocurred in a patient with resolved hepatitis. Two patients who developed acute hepatitis B were HBV naive and previously immunized patients, respectively. Hepatitis B virus reactivation remains a problem in seropositive patients and might require more effective treatment strategies.