Early oesophageal and gastric cancer are unique forms of oesophageal and gastric carcinoma with an excellent prognosis. Remarkable changes have taken place in the epidemiology of upper gastrointestinal malignancies. In particular, the incidence of adenocarcinoma of the distal oesophagus and the gastric cardia has risen over the past two decades. In the United States and Europe, early detection is dependent on a low threshold for upper gastrointestinal endoscopy with biopsy, because specific symptoms and physical findings are rarely present in patients with early oesophageal and gastric cancer. In addition to histology, the detection of possible markers of malignancy, such as aneuploidy (detected by flow cytometry) and the presence of oncogenes and tumour-suppressor genes, in biopsy material may be of value in the diagnosis of early cancers. For patients with early oesophageal or gastric cancer, surgery offers the best hope of cure. If patients are at high risk for surgery, an endoscopic resection may be an alternative option. This review discusses the definitions, the changes in epidemiology, the current options for diagnosis and treatment, and the value of screening programs for patients with early oesophageal or gastric cancer.