Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 21 01 2026 05 19 36 45 Parisa Mahjoobi Department of Medical Parasitology and Mycology, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran Amir Bairami Department of Parasitology and Mycology, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran. Aliehsan Heidari Department of Medical Parasitology and Mycology, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran Saeed Bahadory Vice-Chancellor of treatment, Imam Hassan Hospital, Alborz University of Medical Sciences, Alborz, Iran. 2025 06 02 Background and Aim: Child labor (CL) is the exploitation of children through any work or activity that interferes with their ability to attend school or is harmful to their mental, physical, social or moral well-being. Unfortunately, child laborers are a shadow population for which specific information on the prevalence of intestinal parasites is not available. The present study aimed to estimate the prevalence of intestinal parasites among child laborers in Karaj-Alborz. Methods and Materials: The present study was conducted with a cross-sectional design between 2020 and 2022 in Karaj-Alborz. Two hundred and three stool samples were collected from working children in Karaj and its suburbs. The samples were examined for the presence of intestinal parasites at Alborz University of Medical Sciences using parasitological techniques (e.g., t smear, Formalin-Ether concentration, modified trichrome staining and Ziehl-Neelsen staining). Result: The prevalence of intestinal parasites in CLs was estimated at 76% (156/203), of which 76.4% (155/156) were associated with protozoa and 1/203 (0.5%) with helminths. The highest prevalence was related to the protozoan Blastocystis hominis (89 cases (43.8%)) and among the pathogens, 11 cases (5.4%) of Giardia duodenalis were isolated. Conclusion: The significant and alarming prevalence of intestinal parasites in CLs requires preventive, supportive, and therapeutic measures for this vulnerable population. Further attention focusing on the health status of child laborers is recommended in future studies https://ijpa.tums.ac.ir/index.php/ijpa/article/view/4628 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/4628/1477