Aim: Primary immunodeficiencies (PIDs) are a heterogeneous disorder group characterized by an impaired immune system, leading to an increased susceptibility to infections and a wide range of clinical manifestations, including gastrointestinal (GI) complications. This study aimed to assess the GI manifestations of PID patients and highlight the significance of atypical gastrointestinal symptoms in the early diagnosis of these patients. Methods: A retrospective analysis was conducted on pediatric patients diagnosed with PIDs at Selcuk University Medical Faculty from 2011 to 2021. The study focused on demographic data, clinical presentation, genetic mutations, and GI manifestations, including endoscopic evaluation. Patients were categorized according to the International Union of Immunological Societies (IUIS) PID classifications. Statistical analyses were performed to identify significant associations between PID types and GI manifestations. Results: The cohort comprised 101 patients, with 46% presenting with GI symptoms, including malnutrition and chronic diarrhea, as the most common findings. Primary antibody deficiency (PAD) emerged as the most prevalent PID with GI involvement, followed by combined immunodeficiencies (CID) with associated or syndromic features. Endoscopic evaluations revealed inflammatory bowel disease (IBD)-like colitis in a significant subgroup of patients. The analysis showed that some GI symptoms were more common in specific PID categories, highlighting the importance of early gastroenterological assessment in PID patients. Conclusion: Recognition of common GI symptoms in pediatric patients with PIDs may facilitate early diagnosis and prompt multidisciplinary management, potentially improving patient outcomes. The study highlights the necessity of considering PIDs in diagnosing persistent or severe GI symptoms in children.