The endoscopic diagnosis, staging, and therapy of gastrointestinal (GI) malignancies has advanced rapidly and dramatically over the past 15 years. Video-endoscopy has generally replaced fiberoptic endoscopy, and the digitally based fidelity, sharper resolution, and improved magnification of the video-endoscopic image offers a potentially better approach for the evaluation of mucosal abnormalities. Endoscopic diagnosis of GI malignancies has been enhanced by the recent development of selective vital staining techniques of mucosal abnormalities and more sensitive and aggressive biopsy techniques. The recent dissemination of endoscopic ultrasound has propelled preoperative TNM staging into a new realm of accuracy and has afforded additional potential for directed biopsy techniques. Therapy of GI malignancies has advanced through the development of thermal and nonthermal laser technology, tumor probes, expandable stents, and endoscopic resection techniques.