It is well known that the event of hepatitis B virus reactivation can occur among patients undergoing treatment for hematological malignancies. In this paper we will present the available data regarding the risk of hepatitis B virus reactivation in this special population of immunosuppressed patients and explore the relevance of an accurate prevention and management of this condition. A computerized literature search was performed using appropriate terms arrangement, including English-written literature only or additional relevant articles. The evaluation of hepatitis B reactivation risk is a multidimensional process, which includes conducting an accurate clinical and physical history, considering the virological categories, the knowledge of the medication chosen to treat these hematological malignancies and the induced grade of immunosuppression. Adopting adequate preventive strategies and surveillance according to the current international recommendations is crucial to prevent HBVr and its dire clinical consequences (hepatitis, liver failure, interruption of lifesaving anti-neoplastic treatments). Universal HBV screening of patients scheduled to undergo treatment for hematological malignancies should be the chosen policy, and clinicians should be aware of the inherent risk of viral reactivation among the different virological categories and the classes of immunosuppressive drugs.