Data from recent studies suggest rising incidence rate of hepatitis E virus (HEV) infection in the UK. HEV infection may take a severe and persistent course in immunocompromised patients, including transplant recipients on immunosuppressives, patients with HIV, haematological malignancies and in idiopathic CD4+ T lymphocytopenia. The prevalence of HEV in primary antibody deficiency (PAD) disorders is still unknown. The aim of this study was to investigate HEV infection in 27 patients with PAD with unexplained, persistently elevated liver enzymes. Although all the 27 patients tested negative for HEV-RNA, we would still strongly recommend that HEV should be considered in any immunodeficient patient with impaired liver function.