en Infectious diseases and public health Infectious diseases and public health Original article Original article <strong>Introduction: </strong>Rodents are known as the reservoir of various zoonotic diseases and play a critical role in the transmission of pathogenic agents to humans. During an investigation on rodent reservoirs of leptospirosis in Caspian Sea littoral, northern Iran, we took advantage of the opportunity to examine the animals for intestinal helminth infections. <strong>Methods: </strong>We received gastrointestinal tracts (GITs) of 132 rodents belonged to the genus <em>Rattus,</em> from Mazandaran, Gilan and Golestan Provinces. The GIT of the animals had been preserved in 10% formalin and transferred to Helminthology Laboratory of School of Public Health, Tehran University of Medical Sciences. We examined the GITs contents for helminths under a binocular followed by a microscope with different magnifications and identified the specimens according to reliable morphological keys. <strong>Results:</strong> Out of the 132 rats, 83 (62.87%) harbored helminth parasites. We identified 11 helminth species among which the zoonotic cestodes, <em>Hymenolepis</em> <em>diminuta</em> (29.5%) and <em>Hymenolepis nana</em> (18.18%) exhibited the highest prevalence. The species<em> Euparyphium murinum </em>and <em>Skerjabinotaenia abnormalis</em> are reported here for the first time from Iran. <strong>Conclusion: </strong>The Caspian Sea littoral of Iran is a suitable area for the breeding of the commensal rodents. In this study, the rats from this area exhibited a high burden of helminth infections, with some species of public health importance. Rattus spp., Intestinal parasites, Caspian Sea, Iran. 32 36 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-173-1&slc_lang=en&sid=1 Nahideh Mazhari saba.mazhari@gmail.com 0000-0002-7807-9113 Yes Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences (TUMS), Tehran, Iran. Parisa Moosavi pra.mousavi@gmil.com 0000-0003-1425-715x No Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences (TUMS), Tehran, Iran. Ehsan Mostafavi mostafaviehsan@gmail.com http://orcid.org/0000-0002-1997-517X No Department of Epidemiology, Pasteur Institute of Iran, Tehran, Iran Behzad Esfandiari esfandiari88@gmail.com 0000-0002-3665-6306 No Laboratory of Animal Sciences, Pasteur Institute of Iran, Tehran, Iran Iraj Mobedi mowlavig@gmail.com 0000-0003-2715-0909 No Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences (TUMS), Tehran, Iran. Bahman Rahimi Esboei bahman5164@yahoo.com 0000-0003-2595-9907 No Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences (TUMS), Tehran, Iran. Gholamreza Mowlavi molavig@yahoo.com 0000-0002-3539-7058 No Department of Medical Parasitology & Mycology, School of Public Health & Institute of Public Health Research, Tehran University