Diseases presenting with dyspepsia fall into two general categories: organic and functional. Overall, most patients with dyspepsia have no underlying identifiable disease process. The diagnostic yield of organic causes is less in younger patients, and, conversely, serious organic lesions are common in elderly dyspeptic patients. The commonest organic causes of dyspepsia are peptic ulcer disease, gastroesophageal reflux, biliary tract disease, and gastric cancer. Symptoms and physical signs may help to differentiate these organic causes from functional dyspepsia but endoscopic or radiographic/ultrasound studies are usually necessary to ensure the appropriate diagnosis. Less common organic causes of dyspepsia not to be overlooked include drugs, pancreatitis, malabsorption syndromes, metabolic disorders, ischemic heart disease, and collagen vascular disorders.