In a prospective study paired sera of 14 patients suffering from Bell's palsy were examined for antibodies against Varicella-zoster Virus (VZV), Herpes-simplex Virus (HSV), Cytomegalovirus (CMV) and Epstein-Barr Virus (EBV). For determination of antibodies against VZV, HSV and CMV an enzyme-linked immunosorbent assay was carried out. Indirect immunofluorescence was carried out to determine antibodies against EBV. Serum samples were taken within 5 days of Bell's palsy having been diagnosed and were compared with further serum samples taken 4 weeks later. No evidence of significant differences between the antibody titers of the paired sera was found. The viral etiology of Bell's palsy due to an exogenous infection or by activation of a latent infection seems unlikely.