Systemic amyloidosis is a rare disease characterized by extracellular accumulation of amyloid protein in one or more organs. Inpatients with systemic amyloidosis, the most frequently affected organs are kidney and heart, followed by the nervous system,soft tissues, and lungs. Small bowel and liver involvement are also frequent in systemic amyloidosis. Gastrointestinal (GI) findingsare common, and the degree of organ involvement determines the symptoms. Patients usually have nonspecific findings suchas abdominal pain, nausea, diarrhea, and dysphagia, which may delay the appropriate diagnosis. Liver involvement occurs in themajority of patients, but the symptoms typically do not happen unless a marked hepatic amyloid deposition occurs. Diagnosis is bytissue biopsy. Treatment and prognosis depend on the underlying disease. GI system involvement is a sign of poor prognosis. In thiscase series, five patients who were diagnosed with gastrointestinal system amyloidosis in our clinic are presented.