A 37-year-old man presented with left upper abdominal pain for 13 months. Laboratory examinations showed elevated peripheral eosinophils. Chest CT showed thickened wall of the entire esophagus. FDG PET/CT was performed showing diffuse FDG uptake in the thickened esophageal wall. Esophageal endoscopy showed pale and edematous mucosa. Histologic examination of the esophageal biopsy specimens revealed marked eosinophil infiltration of the mucosa. The clinical and pathologic findings were consistent with eosinophilic esophagitis (EoE). This case indicates EoE should be included in the differential diagnosis of abnormal FDG accumulation in the esophageal wall along with malignant and nonmalignant conditions.