Patients with obstructing cancers are ineligible for preoperative chemotherapy and radiation unless they undergo surgical diversion. Endoscopic laser therapy (ELT) may provide an alternative to colostomy for these patients. We retrospectively reviewed all patients with distal sigmoid and rectal carcinomas who underwent ELT from January 1988 through April 1990. The majority of patients were referred for palliation of advanced disease. Thirty-seven patients underwent 123 ELT sessions (median, 2.5; range, one to 18). In 84% of patients, patency was maintained during a median follow-up of 31.5 weeks (range, one to 123). Morbidity and mortality were 2.5% (3/123) and 5% (1/37), respectively. Sixty-two percent had radiotherapy, chemotherapy, and/or surgery concurrent with ELT. Endoscopic laser therapy can safely and effectively reestablish and maintain luminal patency in patients with obstructing distal cancers. In addition, ELT can enable the administration of preoperative adjuvant radiotherapy and chemotherapy.