HBsAg-negative/HBcAb-positive haematopoietic stem cell transplant (HSCT) recipients are at high risk of hepatitis B virus (HBV) reactivation. Allogeneic HSCT recipients from years 2000 to 2010 were evaluated in order to study the impact of being HBsAg-negative/HBcAb-positive in this population. Overall, 137 of 764 patients (18%) were HBsAg-negative/HBcAb-positive before HSCT. Overall survival, non-relapse mortality (NRM), acute and chronic graft-vs.-host disease were similar in HBcAb-positive and HBcAb-negative patients. Reactivation occurred in 14 patients (10%) within a median of 19 months after HSCT (range 9-77). Cause-specific hazard for reactivation was decreased in the case of an HBV-immune/exposed donor (HRadjusted = 0.12; 95% CI, 0.02-0.96; p 0.045) and increased in patients who received rituximab treatment (HRadjusted = 2.91; 95%CI, 0.77-10.97; p 0.11). Competing risk analyses documented a protective role of an HBV-immune/exposed donor (p 0.041) and an increased probability associated with the length of treatment with cyclosporine (p <0.001) and treatment with rituximab (but not with low-dose rituximab prophylaxis, p <0.001 at each landmark point). No differences in overall survival and NRM were found between patients with and without HBV reactivation. The donor’s immunity was independently and consistently associated with a decreased risk of HBV reactivation, while rituximab and cyclosporine treatments increased the probability.