Background: The etiology of the Guillain-Barre syndrome (GBS) is not clear; in many cases, GBS is triggered by a bacterial or viral illness. Objectives: To evaluate the role of active infection with Herpesviridae group and its association with this syndrome we have investigated the cerebrospinal fluid (CSF) and serum of patients with GBS for detection of these viruses. Patients and Methods: In a prospective and cross sectional study, CSF and serum samples were obtained from 15 consecutive patients admitted with GBS in the department of neurology in a university-affiliated children’s hospital in Tehran. Patients had been diagnosed with GBS based on clinical and paraclinical findings. The level of IgM and IgG antibodies to Herpes simplex virus (HSV), Epstein–Barr virus (EBV), and Cytomegalovirus (CMV) were tested by enzyme linked immunosorbent assay, (ELISA) in CSF and serum. A highly sensitive polymerase chain reaction (PCR) assay was also used for virus detection in all samples. Results: We detected viral DNA in 3 of 15 patients revealing current systemic or central nervous system (CNS) virus infection; in 2 cases CMV PCR had positive results in serum and in one case HSV PCR had positive findings in CNS. Conclusions: The clinical significance of this finding has yet to be elucidated but we showed footprint of Herpes viruses in some patients with definite GBS.