Background Eosinophilic gastrointestinal diseases (EGIDs) are defined by marked eosinophilia in the gastrointestinal (GI) tract resulting in a wide variety of GI symptoms. When accompanied by blood hypereosinophilia (HE; absolute eosinophil count ≥1500/mm3), EGID can occur as an isolated GI disorder (hypereosinophilic syndrome [HES]/EGID overlap) or as part of a multisystem hypereosinophilic syndrome (Multisystem HES). Objective To describe the GI disease of patients categorized as those with HES/EGID overlap versus those with Multisystem HES. Methods Consecutively enrolled patients on a natural history protocol to study eosinophilia with biopsy-proven EGID involving the esophagus, stomach, small-bowel, and/or colon were evaluated for clinical, histopathologic, and endoscopic features by retrospective chart review. Results Among the 56 patients with EGID and HE, 34 were categorized as HES/EGID overlap and 22 as Multisystem HES. Demographics, GI symptoms, and associated comorbidities were similar between the 2 groups. Multisegment GI eosinophilia was present in 20 of 30 (67%) patients who underwent tissue sampling of all 4 GI segments. Tissue eosinophilia in all 4 GI segments was found in 5 of 30 (17%) patients. Dietary therapy was more common in patients with HES/EGID overlap (65% vs 23%, P = .0028). Patients with Multisystem HES were more likely to receive glucocorticoids (100% vs 79%, P = .0349) and nonglucocorticoid systemic therapies (77% vs 38%, P = .0061). One-third (8 of 22) of patients with Multisystem HES presented with isolated GI symptoms before developing extraintestinal manifestations at a median of 1 year (range, 0.25-15 years). Conclusion There are striking clinical similarities between patients with Multisystem HES and those with HES/EGID overlap, despite differing treatment approaches. Moreover, Multisystem HES can present with isolated GI involvement. Larger prospective studies are needed to confirm these findings.