Objective : Gastrointestinal (GI) involvement by primary systemic amyloidosis is rare, comprising of 8 % of all cases and only 1 % is symptomatic. Patients with gastric amyloidosis may present with upper GI bleeding, nausea/vomiting, and weight loss. Herein we reported a case of multiple myeloma with co-occurring gastric amyloidosis and Helicobacter pylori-associated gastritis presenting with massive upper GI bleeding. Method : Case report of gastric amyloidosis with endoscopic, and histological studies. Results : A 86-year old Thai male with underlying multiple myeloma and hepatitis B viral cirrhosis had passed black watery stool for 3 days with palpitation and fainting. No hematemesis, nausea/vomiting or abdominal pain was complained. Physical examination revealed hypotension and mild pallor without signs of chronic liver disease except mild jaundice. Abdomen was soft, with no palpable mass. Per rectal examination revealed melena. Esophagogastroduodenoscopy revealed diffuse severe gastroduodenitis with a superficial gastric ulcer. Biopsy of antrum showed mild degree of chronic active gastritis associated with H. pylori. In addition, extracellular deposition of Congo-red-positive eosinophilic material in lamina propria and muscularis mucosae was observed. Gastric amyloidosis was diagnosed. Twenty five days after admission, patient died of cardiac failure with sepsis. Conclusion : A case of gastric amyloidosis with H. pylori-gastritis was reported.