In hematologic malignancy patients with HBsAg positivity, the risk of hepatitis B reactivation is high in cases of high dose use of corticosteroids, rituximab, chemotherapy agents belonging to the anthracycline group and stem cell transplantation. HBV reactivation has been reported in the literature generally in HBsAgnegative, anti-HBc IgG- and anti-HBs-positive lymphoma patients in case of stem cell transplantation or use of rituximab as a chemotherapeutic agent. There are publications that report cases of HBV reactivation in HBsAg-negative multiple myeloma patients who have recieved bortezomib and/or stem cell. In this article, we present a multiple myeloma case with full recovery from HBV infection developing an acute hepatitis due to HBV reactivation after bortezomib use and autologous bone marrow transplantation. Finally, it was successfully treated with lamivudine. It is aimed to draw attention to the fact that hepatitis B serologic markers should be closely monitored for possibility of reactivation of hepatitis in candidates of chemotherapy/stem cell transplantation recovering from HBV infection.