Eosinophilic gastrointestinal disease (EGID) is an emerging condition worldwide in both children and adults, although it is considered rare. EGID has been underestimated owing to its underdiagnosis in the past, and its prevalence has recently increased. The diagnosis of EGID is based on histopathologic findings of endoscopic mucosal biopsy in which the total number of infiltrating eosinophils in each segment of the gastrointestinal tract is determined in patients with chronic or recurrent gastrointestinal symptoms despite a lack of consensus or guidelines on the definition of tissue eosinophilia except for eosinophilic esophagitis. Laboratory findings, including peripheral eosinophilia and increased fecal calprotectin levels, may be additional clues for detection of EGID in practice. Individualized treatment strategies, including adequate dietary modification and pharmacological therapy, may improve clinical outcomes of pediatric patients with EGID.