Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 17 3 2022 09 05 415 419 Keyhan Ashrafi Department of Medical Parasitology and Mycology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran Maryam Atri Student Research Committee, Guilan University of Medical Sciences, Rasht, Iran Farshid Saadat Department of Immunology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran Elham Hajialilo Department of Medical Parasitology and Mycology, Qazvin University of Medical Sciences, Qazvin, Iran Behnaz Rahmati Department of Medical Parasitology and Mycology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran Meysam Sharifdini Department of Medical Parasitology and Mycology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran 2021 11 14 2022 09 05 We report a case of Hymenolepis diminuta infection in a two years old boy living in Guilan Province, northern Iran diagnosed in 2019. The patient was complained of anorexia, weight loss, weakness and disturbed sleep. Stool examination revealed numerous eggs of H. diminuta. After treatment with a single dose of oral praziquantel, the patient recovered without evidence of the egg shedding in follow-up stool samples. Moreover, we performed detailed phylogenetic analysis of the H. diminuta comparing with other isolates deposited in GenBank database based on Cox1 gene. Based on BLAST analysis of Cox1 gene our sequence showed 97.4-99.2% similarity with those of H. diminuta available in GenBank. The present study recommends the importance of reporting the infection cases, in order to improve knowledge on epidemiology and control of the neglected disease. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/3505 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/3505/1238