Tumours in the oesophagus, stomach and large bowel represent a substantial proportion of the burden of cancer mortality. Endoscopy provides the most effective method of detecting premalignant and malignant precursors of advanced cancer in which the tumour process is restricted to the superficial layers of the digestive - tract wall. To ensure reliable detection, consensus guidelines on the morphological classification of the endoscopic appearance of these precursors need to be adopted. In 2002, a workshop was held in Paris to explore the relevance of the Japanese endoscopic classification of superficial neoplastic lesions of the GI tract. A further meeting was organized in Osaka in 2003 in relation to the definition of the subtypes used in endoscopy. For gastrointestinal endoscopy to become more effective in reducing the morbidity and mortality it is important for endoscopists to recognize both polypoid and non polypoid cancer precursors.