Background: Adenotonsillar hypertrophy (ATH) is a common problem in children that causes the obstruction of airways and other relevant complications. Helicobacter pylori (H. pylori) is considered one of the microbial causes of ATH development. Objectives: The study aimed to determine the H. pylori colonization in patients with adenotonsillar hypertrophy and assess the prevalence and clinical characteristics of colonized patients and possible association with complications. Methods: This study was carried out on 114 children with ATH referring to the Bouali Hospital of Sari from December 2017 to December 2018. Adenotonsillar samples were prepared from the right and left tonsils and adenoid of each patient. The Rapid Urease test (RUT) and nested-PCR were performed on the samples. Data analysis was performed with SPSS version 20 software. Results:The participants included 52 females and 62 males with a mean age of 7.19 ± 3.08 years. The RUT was positive for 59 participants: 26 in right tonsil, 31 in left tonsil, and two in adenoid samples. Helicobacter pylori was detected in the adenotonsillar tissue of 95 patients using nested-PCR. No significant association was found between the PCR results and gender (P = 0.123). Conclusions: This study approved the presence of H. pylori in the adenotonsillar tissue of children with ATH and highlighted the concept that the pharynx could be an extra gastric reservoir of H. pylori. However, we failed to prove an association between H. pylori adenotonsillar colonization with ATH and acute otitis media.