Patients with hepatitis B virus (HBV) infection may be coinfected with other viral diseases, such as hepatitis C virus (HCV) and/or D virus (HDV), or have serious diseases secondary to the hepatitis, such as hepatocellular carcinoma. These coexisting conditions have an impact on the success of treatment and of liver transplantation. Patients with HBV and HDV are at lower risk for HBV recurrence than are patients with HBV alone; likewise, patients with HBV/HCV coinfection appear to have a higher 5-year survival rate posttransplantation. Treatment of coinfection is similar to that used for HBV alone. Hepatitis B immune globulin and interferon have been found to be effective in varying degrees. Recurrence or reinfection of disease after liver transplantation presents many clinical problems that will require new therapeutic approaches. Future studies will help to begin solving these challenges.