Study design: Prospective clinical study. Methods: Forty-six children aged 0-16 years with facial palsy comprised the study group. Paired serum samples and cerebrospinal fluid were tested to find indications (antibodies, growth of the microbe, or nucleic acids) of microbes putatively associated with facial palsy. The microbes tested were herpes simplex virus-1 and -2, varicella-zoster virus, human herpesvirus-6, Mycoplasma pneumoniae, Borrelia burgdorferi, influenza A and B-, picorna-, cytomegalo-, parainfluenza-, respiratory syncytial-, coxsackie B5-, adeno-, and enteroviruses, Chlamydia psittaci, and Toxoplasma gondii. Besides the routine tests in clinical practice, serum and cerebrospinal fluid samples were tested with a highly sensitive microarray assay for DNA of herpes simplex virus-1 and -2, human herpesvirus-6A , -6B, -7, Epstein-Barr-, cytomegalo-, and varicella-zoster viruses.