Abstract We report the case of a 3-year-old boy with Mntriers disease who presented with prominent anasarca associated with hypoproteinemia, but no proteinuria. An early sonogram of the stomach demonstrated thickening of the gastric wall which was found to resolve gradually on serial sonograms. Consequently, we considered that the submucosal layer of the gastric wall was particularly thickened as a result of Mntriers disease. A gastric biopsy was performed 18 days after onset of the disease, and an electron-microscopic examination of the sample disclosed persistent widening of gastric tight junctions by more than 10 nm. The patient made a full recovery on supportive treatment in 3 weeks. Ultrasonography provided us with a potent tool not only in making the diagnosis, but also in following the course of the disease.