Ménétrier disease is a very rare chronic gastric disorder characterized by gastric mucosal hypertrophy. We present a case of Ménétrier disease with CT, MRI, and FDG PET/CT findings. Enhanced CT and MRI showed diffuse thickened mucosa of the greater curvature and elongated mucosa of the antrum with remarkable enhancement. The early and delayed FDG PET/CT showed increased FDG uptake of these thickened mucosa. The increased FDG uptake may be due to the mucosal inflammation. This case indicates Ménétrier disease should be included in the differential diagnosis of abnormal gastric FDG accumulation along with tumor and nontumor processes.