The technical difficulties related to the insertion of a long intestinal tube into the jejunum under fluoroscopy present a considerable problem in patients with an intestinal obstruction.To evaluate the usefulness of endoscopic long intestinal-tube placement with the ultrathin esophagogastroduodenoscope (UT-EGD).A prospective randomized clinical trial was conducted.Twenty-eight consecutive patients who presented with an intestinal obstruction were included in the study.The UT-EGD was inserted nasally into at least the second portion of the duodenum or beyond. After a guidewire was introduced through the working channel, with fluoroscopic guidance, the UT-EGD itself was carefully removed with the guidewire left in place. Next, a hydrophilic intestinal tube was advanced over the guidewire into the jejunum, and then the guidewire was removed.Primary end points are the total procedure time, the radiation exposure time, and the rate of complications, all compared with the conventional method.The mean (+/-SD) total procedure time was 18.7 +/- 8.4 minutes for the UT-EGD method and 39.5 +/- 15.0 minutes for the conventional method, with a significant time difference between the 2 methods (P.0005). The mean (+/-SD) radiation exposure time was also shorter with the UT-EGD method (11.1 +/- 6.0 minutes) than with the conventional method (30.3 +/- 13.7 minutes) (P.0005). There were no complications, except for mild nasal bleeding with each method.The UT-EGD method has definite advantages in the placement of a long intestinal tube for patients with an intestinal obstruction in comparison with the conventional method.