It is still a matter of debate whether nucleoside/nucleotide analogues should be administered as prophylaxis to hepatitis B surface antigen (HBsAg)-negative/antibodies against hepatitis B core antigen (anti-HBc)-positive patients with immunosuppression or whether these patients should be closely monitored and early treatment administered to those who become HBsAg-positive. We describe a reactivation of occult HBV infection emerging with the case of acute hepatitis B in the wife of an HBsAg-negative/anti-HBc-positive subject treated with rituximab-based chemotherapy for chronic lymphocytic leukaemia.