Both Nd:YAG laser and photodynamic therapy (PDT) have ideal indications in endoscopic treatment of gastrointestinal (GI) tumors. A retrospective analysis of 3,505 Nd:YAG laser treatments in 1,015 patients revealed that recanalization of inoperable tumors can be obtained in 93% and 97% of patients with upper and lower GI neoplasms, respectively. Subjective improvement of symptoms was achieved in 74% and 97%, respectively. The overall morbidity and mortality rates were 3% and 1%, respectively, for upper GI tumors and 3% and 0.5% for lower GI tumors. Colorectal adenomas were eradicated in 84% of cases, with a morbidity and mortality of 5% and 0%, respectively. Early stage esophageal and gastric carcinomas were treated with Nd:YAG laser when lesions had well-defined borders or protruded over the mucosal surface and with PDT (38 PDT cycles in 27 patients) in the case of undefined borders or ulcerated lesions. The cure rate was 73% for esophageal tumors and 85% for gastric tumors. Sunburns after photosensitization and local complications occurred in 7% and 6% of patients, respectively. No death was related to endoscopic treatment.