We present a case in which an elderly woman diagnosed with a splenic marginal zone lymphoma (MZL) was found to have positive Hepatitis B serology. Link with Hepatitis C virus is well documented but reports of association of Hepatitis B virus (HBV) with splenic marginal zone lymphoma are still emerging. A 69-year-old lady presented with weight loss, pancytopenia and marked splenomegaly. Prior to commencing treatment, Hepatitis B serology confirmed Hepatitis B infection. She was treated with Chlorambucil along with anti-hepatitis B prophylaxis and HBV PCR monitoring. She had an excellent response to treatment with resolution of symptoms and splenomegaly. This case highlights the importance of testing for hepatitis B serology in patients diagnosed with splenic MZLs as causative agent. Although the association between HCV is well documented in the literature, a relationship between HBV may also be important. Also, chemotherapy +/- Rituximab for splenic MZL is associated with the reactivation of latent infections; hence providing prophylactic cover for pre-existing latent HBV infection may be required to prevent reactivation as in this case.