Background: Endoscopic palliation of malignant esophageal obstruction with uncovered self-expanding metal stents has been shown to have fewer complications than with conventional plastic stents. The addition of a membrane might prevent tumor ingrowth and allow treatment of digestive-respiratory fistulas. We report the clinical experience with a prototype silicone membranecovered self-expanding metal stent. Methods: Twenty-three silicone membrane-covered Wallstent prototypes were used in 21 patients with dysphagia due to inoperable malignant tumors involving the esophagus and cardia. Results: Stent implantation was technically successful in all patients. There were no procedure-related perforations or deaths. The prototype stent was successful in sealing seven of the eight (87.5%) digestive-respiratory fistulas. As a group, the mean dysphagia grade improved significantly after stent placement (4.8 ± 0.9 vs 3.4 ± 1.6, P < 0.0005). However, 9 of 21 (42.9%) patients experienced no improvement in their dysphagia. Complications occurred in 13 of 21 (61.9%) patients. Tumor ingrowth was not observed in any patient. Conclusions: The prototype covered self-expanding metal stent was effective in sealing digestive-respiratory fistulas and provided palliation of dysphagia in slightly more than one half of the patients stUdied. A great deal has been learned from the preliminary experience, which has led to design modifications. The utility of the commercially available device should be evaluated in further prospective clinical trials.