We report the case of a 57-year-old woman with abdominal discomfort. The patient had anemia and hypoalbuminemia. Esophagogastroduodenoscopy and colonoscopy revealed diffuse infiltrative lesions at the stomach, duodenum, and ascending colon. Multiple biopsies were taken and histological examination of the biopsies from the stomach, duodenum and colon showed amyloid deposits stained positively with Congo red. Immunohistochemistry study showed positive sign of kappa and lambda chain at light chain stain. In addition, monoclonal components at serum electrophoresis confirmed the diagnosis of amyloid light-chain amyloidosis. The patient was treated with thalidomide and dexamethasone.