The aim of the present study was to verify the potential association between multiple myeloma (MM) and hepatitis B/C virus (HBV/HCV) infection. This retrospective case-control trial included 299 patients with MM and 299 patients with acute leukemia (AL). Age and sex were matched between the two groups. The hepatitis B surface antigen (HBsAg) positivity rate was significantly higher in the MM group (19.4% vs. 12.0% in patients with AL; p = 0.014). The rate of HCV infection did not differ between the two groups. The incidence of cirrhosis was significantly higher in HBsAg+ patients (17.2% vs. 6.2% in HBsAg- patients; p = 0.011). The rate of hepatitis E virus (HEV) infection was also significantly higher in HBsAg+ patients (5.2% vs. 0.4% in HBsAg- patients; p = 0.025). Hepatic damage was much more common in HBsAg+ patients than in HBsAg- patients both prior to (22.4% vs. 8.7%; p = 0.006) and during chemotherapy for MM (67.2% vs. 28.6%; p < 0.001). ISS stage, HBsAg+, the use of bortezomib and thalidomide and autologous stem cell transplant were significant factors for overall survival in univariate analysis. In the Cox regression analysis, ISS stage (p = 0.027), HBsAg+ (p = 0.042) and the use of thalidomide (p = 0.001) showed a significant effect on the OS of these patients. The prevalence of HBV infection is higher in patients with MM than in subjects with other hematological malignancies such as AL. Hepatic injury is more common in patients with MM with HBV infection, particularly during chemotherapeutic treatment. HBsAg positivity may be a prognosis factor in patients with MM in HBV endemic areas.