We report the effective clinical use of endoscopic laser in Japan using the results of a nationwide survey and our own experience with more than 100 cases. The Nd:YAG laser and argon dye laser with hematoporphyrin derivative (photodynamic therapy) were most commonly used in digestive endoscopy and were investigated as new modalities of cancer therapy. Photodynamic therapy was fairly effective, especially in superficial esophageal cancer and the ill-defined lesions of early gastric cancer. Endoscopic laser treatment was carried out on 80 patients with 86 lesions of early gastric cancer at our hospital, and the following tumor types were proven highly curable by this means: focal cancer, IIa and so-called "gastritis-like" tumors less than 2 cm in size. The Nd:YAG laser provides a new approach to palliative treatment, such as recanalization of neoplastic obstruction in the advanced stage of gastrointestinal cancers.