This study assesses the outcome of 20 patients referred for neodymium: yttrium-aluminum-garnet laser therapy of malignant duodenal tumors between 1984 and 1992. Almost all (95%) of these patients required palliative therapy for gastrointestinal hemorrhage, and nearly half (45%) also had obstructive symptoms. A mean of 3 (range, 1 to 6) laser treatment sessions were required for palliation. Laser therapy eliminated the need for blood transfusions in only 38% of patients. Obstructive symptoms were improved in all patients after laser treatment. Treatment failure could not be predicted on the basis of demographic factors (other than age), tumor characteristics, or transfusion requirements. Survival after laser therapy was 30% at 6 months and 15% at 12 months. Endoscopic neodymium:yttrium-aluminum-garnet laser therapy is a reasonable approach for palliation of malignant tumor obstruction or hemorrhage in selected cases; however, hemorrhage often continues.