Chronic hepatitis B virus (HBV) infection is a global health problem and has an increased prevalence in patients with Crohn's disease due to their increased requirement for high-risk procedures. A balance between viral replication and host immune response exists and drugs such as the immunosuppressive agents used to treat Crohn's disease may alter this balance. These may result in a hepatic flare, which manifests as high viremia, increased transaminase levels, and hepatic decompensation. The present study describes two cases of hepatic flare thought to be caused by treatment of acute Crohn's disease with systemic corticosteroids and/or azathioprine. Both patients presented with raised transaminase and gamma glutamyl transferase levels and viremia. One patient experienced a decrease in hepatic function, as evidenced by a reduced serum albumin (2.5g/ dL) and jaundice (total bilirubin 5.2 mg/dL), and hepatic decompensation, with ascites. Both patients were treated with the nucleoside analogue entecavir 0.5 mg/day and experienced reductions in HBV-DNA and hepatic enzyme levels within 4-7 days. The patient with decompensation received diuretic therapy and parenteral nutrition to support hepatic function and a clinical improvement was seen. Both patients were discharged 2 weeks after admission and, during follow-up, HBV-DNA levels became negative after 1 and 5 months, respectively. No adverse events were reported in either patient. To the best of our knowledge, this is the first documented report of treatment of HBV flare with entecavir in patients co-affected with Crohn's disease.