en Infectious diseases and public health Infectious diseases and public health Original article Original article <p dir="ltr"><strong>Introduction:</strong> During the past few years, an increasing body of evidence has suggested a possible role for human herpes virus 6 (HHV-6) in Multiple Sclerosis (MS) pathogenesis. Despite the many reports supporting the relationship between HHV-6 and MS, this association has not been definitely proved or refuted, and the matter remains unresolved. The current study was aimed to investigate any relation between HHV-6 viremia and classic MS in patients in Guilan province, Northern Iran. <strong>Method:</strong> HHV-6 viremia was certified by molecular detection in study group (n=46) and control group (n=46) using nested-PCR. Data were analyzed by using three statistical tests (Chi square, odd ratio, and Relative Risk). <strong>Results:</strong> HHV-6 genomic sequences were found totally in 28 out of 46 (60.8%) plasma DNA samples of patients with MS, but were not found in rest of them. It was also found in 13 out of 46 (28.2%) control group. The difference in prevalence of HHV-6 DNA in blood between patients with MS and control group was statistically significant (<em>P</em>=0.0027 and odd ratio=0.277). <strong>Conclusion:</strong> The data of our study showed that HHV-6 can be implicated in the development of MS. We strongly support the need for further, objective, evidence-based examination of the relationship between HHV-6 infection and MS.</p> Human Herpes virus 6, Multiple Sclerosis, Nested PCR, Iran 133 137 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-76-1&slc_lang=en&sid=1 Masoumeh Ahmadi Jalali Moghadam masoumehjalaly@gmail.com No Cellular and Molecular Research Center, Faculty of Medicin, Guilan University of Medical Sciences, Rasht, Iran. Hamidreza Honarmand honarmand.3@gmail.com Yes Department of Microbiology, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, Iran.